Been wanting on for a while, so taking action to make it. We could take inspiration from the other martial half casters, paladin and ranger, but let's make this unique still. Subclasses could be the schools of magic, death knight, and antimage. If you have any ideas feel free to share.

Something like a magus. More around studying and using arcane magic as opposed to like the paladin gaining power through an oatyh and following it, using divine magic, or a ranger gaining more primal or nature bases magic through their bond with nature. They studied both the blade and the eldritch arts, in order to combine the two. It can be done with subclasses or multiclassing sure, but to see a class with its own mechanics around the concept is preferable.

Technically a gish is any character which combines magic and combat, which is a broad definition. 

I find the most enjoyable gishes to play are those which can put their magic into their combat, rather than simply being half a caster one turn, and half a fighter the next.

This was the spellstrike mechanic from the duskblade/magus. However due to the spell structure changes in 5e, spellstrike got turned into smite and strike type spells (think ensnaring strike for an example). These spells were then given to paladin and ranger.

The issue with an official duskblade/magus class if that the mechanics which defined it got stolen by paladin and ranger. So you would need to find a new 'signature feature' for it to really have a place.

Also this is homebrew, so no limits on people making classes they want as long as it's balanced. 

Third_Sundering has made a first draft of a gish class, you might want to check it out.

https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/81077-gish-class-feedback-would-be-nice

Well, as for the primary mechanic, I would prefer spell-strike, but as said above it was stolen, so I was thinking, maybe expending spellslots for an effect on another based on your subclass, but I also feel some subclasses may make it too similar to channel divinity or smite.

Maybe a certain number of your prepared spells, maybe 3, could be prepared separately from others. Those can only be cast on meelee hit, and you must wait at least 2 rounds before using another. Said spells may be switched during preparation, but are only recovered through a 10 minute time spent practicing the movements of each. 10 minutes for 1, 30 for 3.

Or 10 minutes of channelling arcane energy into them, idk.

I've tried many ways of wording the old spellstrike ability into 5e, and it doesn't really work as a direct conversion.

5e changed how spells are listed and how they function. Previously it was touch spells which worked with spellstrike, but now half the damage touch spells are no longer touch, and most touch spells aren't combat related things. In order to include the traditional spells for spellstrike, while excluding the ones which shouldn't be there, you need such a long winded description with so many clauses it doesn't work.

Which is the reason that ability was simply converted into the strike spells.

So I don't think a gish class should have spellstrike as its core feature at all. Sure it should have a huge selection of strike spells (including plenty which paladin and ranger don't get), but it needs something else entirely as its signature feature.

I attempted to make a vampire subclass that was basically an inverted paladin -- it healed through a "blood drinker" ability.

Maybe base yours off paladin as well. Divine smite can be replaced so you can cast a spell targeting that creature by expending a spell slot. If I remember correctly, Paladin's divine smite roughly scales with single-target spells. But now I think I'm remembering that it doesn't.

 idk making new classes is hard. For my vampire class I did what I could to make it unique and I think it came pretty close. For this you face the problem that things like fighter/wizard multiclasses actually do exist.

Hmm the idea of magically summoning your weapons and armour and then creating effects on them is actually really cool. I like that one.

Could be any weapon rather than just a sword?

I like that. It's different enough as a core mechanic and fits well with the theme. 

Quote from Comrade_Jenkens >>

Hmm the idea of magically summoning your weapons and armour and then creating effects on them is actually really cool. I like that one.

Could be any weapon rather than just a sword?

 I'd think it should be allowed to be applied to any weapon, but it should be one you intend to be a "signature" weapon.  So it might be better suited working somewhat like a Pact Weapon.  Call it something else, obviously, but that would give a good framework to build from.

What about an ability to spend the points to make mini walls of force (5ftx5ft)? Summoning cover for allies and blocking off entrances/exits.

Adds a controller/defence aspect.

Class name idea. Bladeweaver?

Home now. Gonna start writing stuff out.

Good idea, I also think we should probably lock the improved versions of the armor and weapon behind lv, and maybe limit the x costs based on lv too.

Doing lv1 stuff now. I'm thinking d10 for hd. Or d8 mayber. Thinking int and con for saves. Martial weapons, light armor, shield, no tools. Then for skills arcana is all I know.

I like it. I'm thinking for lv 1 features Arcane sight, ability to use detect magic a number of times a day equal to proficiency bonus, and mastery points, which are very limited in use for now.

Hey, any update on this? I just finished my second draft of the "arcane gish" class today (Arcknight), and was looking to see what other people had done for inspiration. I already have gotten some ideas from this, and would be excited to see what you ended up doing. 

Oh. Yeah. Might not be the best but it's basically done. Next time I have time not doing work on a pc, I'll type up a doc for it