I feel like if you take shield master, you really want res:dex.
This whole set up arguably works best with a dex based fighter, or a fighter that starts off with a 16 in DEX and STR.
Your shove action relies on Strength Athletics. You're kind of nerfing the main feature if you do a Dex build. The other features do rely on Dex, but this is why I said Barbarians are much better Shield Masters.
I think thats their point is that if you want to take shield master for the DEX save part you are better off taking res:dex.
If you want to shove as a BA it makes sense...honestly you could just take a level of monk and still do that with a spear if you wanted I guess....but you couldn't use a shield.
Overall its probably a blend of theme/mechanics for WHY you want it. Ultimately the feat feels like a half trade for two different feats melded together and its one reason I have not really taken it much.
I've only used it once on a Beast Barbarian, and I found it to be very effective. It was a short campaign, but part proper build and part luck, those Dex saves helped me take 0 damage several times. One of the times it was a fireball, and in a three man party I was the only one left standing. I fed the Paladin a healing potion, and then he got the other guy up. Those bonus action shoves also were FUN and often times effective.
I found a little trick. I could attack, grapple for my second attack, then bonus action shove them prone and I still have them grappled. All with advantage. Then after that I could still use my tail to attack him (normally your hands are tied up so you can't).
I feel like if you take shield master, you really want res:dex.
This whole set up arguably works best with a dex based fighter, or a fighter that starts off with a 16 in DEX and STR.
Your shove action relies on Strength Athletics. You're kind of nerfing the main feature if you do a Dex build. The other features do rely on Dex, but this is why I said Barbarians are much better Shield Masters.
I think thats their point is that if you want to take shield master for the DEX save part you are better off taking res:dex.
If you want to shove as a BA it makes sense...honestly you could just take a level of monk and still do that with a spear if you wanted I guess....but you couldn't use a shield.
Overall its probably a blend of theme/mechanics for WHY you want it. Ultimately the feat feels like a half trade for two different feats melded together and its one reason I have not really taken it much.
I've only used it once on a Beast Barbarian, and I found it to be very effective. It was a short campaign, but part proper build and part luck, those Dex saves helped me take 0 damage several times. One of the times it was a fireball, and in a three man party I was the only one left standing. I fed the Paladin a healing potion, and then he got the other guy up. Those bonus action shoves also were FUN and often times effective.
I found a little trick. I could attack, grapple for my second attack, then bonus action shove them prone and I still have them grappled. All with advantage. Then after that I could still use my tail to attack him (normally your hands are tied up so you can't).
Ah I see so the value is in the "Half if you save but instead you take none" aspect. That is fair.
This spell targets a rope, but due to its casting time, that doesn't matter - the spell will only ever resolve on a different turn from the cast turn, which means the effect is only targeting the Shield Master when it comes up.
When you first cast the spell, it has two targets - the space where the vine is first summoned (which is the primary target for checking for things like casting through total cover) and the creature the vine goes up against. On later turns, if you bonus action command the vine, it's single-target.
Of course, it doesn't only work on spells - e.g. it works against a hunting trap.
I want to point out a distinction. Shield Master doesn't say just single target spells. just spells that only target you. Depending on the interpretation that you take of the wording. This could put onto the list a bunch of spells that Can target others when they do not target others.
Your list is also way too short even if we take the more strict reading that it must be a tingle target spell.
For example. just off the top of my head in the first couple of levels and a note on one from your list...
You forgot The Initial Casting of Create Bonfire (This is only targeting the one with Shield Master when the spell is cast in their space causing them to take the damage from it and making a saving throw against it. Just like the Snare spell while techincally doesn't target them but does only target them when it triggers it's damage effect). The Fact that it hits single targets that pass through it or start their turns on it after that point is a little more grey but arguably single target as well.
Light actually triggers a single target save from a non-willing target if your trying to use it to mark them or some of their equipment to make them glow. Cordon of Arrows for the Same Reasons as Bonfire and Snare.
Grasping Vine doesn't have two targets. it has one target at a time and it has a selected origin point for the effects of attacking that target and successive targets afterward.
Flaming Sphere is another that is single target by technicality despite the fact that it can trigger a secondary effect on multiple targets over the course of a round. Anybody it runs into is just a single target. The questionable part is when anybody that ends their turn next to it is triggering as it's a repeatable single target trigger.
Repeatable Single Target Triggers are really the Crux on how powerful shield master can be in your game because there are a heck of a lot of them. Any Further Damage from Create Bonfire, Web, Hunger of Hadar, and the ending of your turn near Flaming Sphere are just a few that come to mind but there are a vast number more of concentration multiple turn area control spells that specificy specific single target triggers either at the start or end of a persons turn for being in that area. These saving throws and instances of damage or debilitation are technically only effecting one person at a time but they are not limited to only functioning a limited number of times in a Full Round of combat and can trigger potentially on every turn taken in that round. The Way the Spell is worded. The Defensive increase to Dexterity should technically apply to all of these because at the time they are targeting only you.
There are a lot of spells that can trigger a single person per turn to make saves even though they would make multiple people make saves over an Entire Round Potentially. These are potentially all aided by the single target protections of Shield Master. Some of them are even spells that we have a habit of just rolling saves when it is first cast. Despite technically not working that way. Such as Web for example since there is no actual save on it's initial casting, Only the starting of your turn in it's effective area.
I feel like if you take shield master, you really want res:dex.
This whole set up arguably works best with a dex based fighter, or a fighter that starts off with a 16 in DEX and STR.
Your shove action relies on Strength Athletics. You're kind of nerfing the main feature if you do a Dex build. The other features do rely on Dex, but this is why I said Barbarians are much better Shield Masters.
Nerfing? Not necessarily so. After all, this is a fighter we're talking about, and you've got feats aplenty.
For example, let's say I make a STR-based melee half-orc fighter. Assuming point buy, I start out with 17 STR, 15 DEX, and 16 CON, dump the rest. Come level 4, I could take skill expert, increase STR and get expertise in athetlics. Then, at 6 and 8 I'll just take shield master and res: dex. Most campaigns still have plenty of gas left in them by lvl 8, so the build's online. So, now you've got a fighter with a +10 in athletics, and still has at least +6 to their proficient saves. This is pretty great!
If we go on a v.human, oof, we've got even more wiggle room for neat stuff. We could start with +1 in DEX and STR, max them out and set CON to 14. Starting feat can be either skill expert or res:dex to increase DEX to 17 starting. Either way, whatever you didn't pick starting you pick up at 4, then at 6 pick up shield master. This leaves one more feat at 8, which you could totally use for something like SS to compliment a dex-based fighter. You'd have a +9 to athletics even with that set up with a + 7 to your DEX save.
In the end, whether DEX or STR-based, v-human or otherwise, you still have a competitive shield master build that greatly benefits from res: dex without sacrficing their athletics. Even then, if we think about it further, in a typical 1-10 campaign we could even give ourselves the option to multiclass with barbarian after lvl 8 as you only need two levels for danger sense to further enhance the build. If you haven't come across plate armor by that point, you could even forgo wearing armor entirely as your unarmored defense AC will be pretty competitive at that point too and grant you rage benefits too!
I've only used it once on a Beast Barbarian, and I found it to be very effective. It was a short campaign, but part proper build and part luck, those Dex saves helped me take 0 damage several times. One of the times it was a fireball, and in a three man party I was the only one left standing. I fed the Paladin a healing potion, and then he got the other guy up. Those bonus action shoves also were FUN and often times effective.
I found a little trick. I could attack, grapple for my second attack, then bonus action shove them prone and I still have them grappled. All with advantage. Then after that I could still use my tail to attack him (normally your hands are tied up so you can't).
Ah I see so the value is in the "Half if you save but instead you take none" aspect. That is fair.
I want to point out a distinction. Shield Master doesn't say just single target spells. just spells that only target you. Depending on the interpretation that you take of the wording. This could put onto the list a bunch of spells that Can target others when they do not target others.
Your list is also way too short even if we take the more strict reading that it must be a tingle target spell.
For example. just off the top of my head in the first couple of levels and a note on one from your list...
You forgot The Initial Casting of Create Bonfire (This is only targeting the one with Shield Master when the spell is cast in their space causing them to take the damage from it and making a saving throw against it. Just like the Snare spell while techincally doesn't target them but does only target them when it triggers it's damage effect). The Fact that it hits single targets that pass through it or start their turns on it after that point is a little more grey but arguably single target as well.
Light actually triggers a single target save from a non-willing target if your trying to use it to mark them or some of their equipment to make them glow. Cordon of Arrows for the Same Reasons as Bonfire and Snare.
Grasping Vine doesn't have two targets. it has one target at a time and it has a selected origin point for the effects of attacking that target and successive targets afterward.
Flaming Sphere is another that is single target by technicality despite the fact that it can trigger a secondary effect on multiple targets over the course of a round. Anybody it runs into is just a single target. The questionable part is when anybody that ends their turn next to it is triggering as it's a repeatable single target trigger.
Repeatable Single Target Triggers are really the Crux on how powerful shield master can be in your game because there are a heck of a lot of them. Any Further Damage from Create Bonfire, Web, Hunger of Hadar, and the ending of your turn near Flaming Sphere are just a few that come to mind but there are a vast number more of concentration multiple turn area control spells that specificy specific single target triggers either at the start or end of a persons turn for being in that area. These saving throws and instances of damage or debilitation are technically only effecting one person at a time but they are not limited to only functioning a limited number of times in a Full Round of combat and can trigger potentially on every turn taken in that round. The Way the Spell is worded. The Defensive increase to Dexterity should technically apply to all of these because at the time they are targeting only you.
There are a lot of spells that can trigger a single person per turn to make saves even though they would make multiple people make saves over an Entire Round Potentially. These are potentially all aided by the single target protections of Shield Master. Some of them are even spells that we have a habit of just rolling saves when it is first cast. Despite technically not working that way. Such as Web for example since there is no actual save on it's initial casting, Only the starting of your turn in it's effective area.
Nerfing? Not necessarily so. After all, this is a fighter we're talking about, and you've got feats aplenty.
For example, let's say I make a STR-based melee half-orc fighter. Assuming point buy, I start out with 17 STR, 15 DEX, and 16 CON, dump the rest. Come level 4, I could take skill expert, increase STR and get expertise in athetlics. Then, at 6 and 8 I'll just take shield master and res: dex. Most campaigns still have plenty of gas left in them by lvl 8, so the build's online. So, now you've got a fighter with a +10 in athletics, and still has at least +6 to their proficient saves. This is pretty great!
If we go on a v.human, oof, we've got even more wiggle room for neat stuff. We could start with +1 in DEX and STR, max them out and set CON to 14. Starting feat can be either skill expert or res:dex to increase DEX to 17 starting. Either way, whatever you didn't pick starting you pick up at 4, then at 6 pick up shield master. This leaves one more feat at 8, which you could totally use for something like SS to compliment a dex-based fighter. You'd have a +9 to athletics even with that set up with a + 7 to your DEX save.
In the end, whether DEX or STR-based, v-human or otherwise, you still have a competitive shield master build that greatly benefits from res: dex without sacrficing their athletics. Even then, if we think about it further, in a typical 1-10 campaign we could even give ourselves the option to multiclass with barbarian after lvl 8 as you only need two levels for danger sense to further enhance the build. If you haven't come across plate armor by that point, you could even forgo wearing armor entirely as your unarmored defense AC will be pretty competitive at that point too and grant you rage benefits too!