Okay, the Giant Soul Sorcerer bloodline has me jazzed about playing a sorcerer. Why didn't they bring this out when Storm King's Thunder debuted! It would have made for some great thematic PCs, and NPCs!
At the moment I'm leaning towards Storm or Frost. What does everyone else like?
Getting additional known spells is sooooooo very appealing for a sorcerer. And I feel like it's a perfectly adequate amount; not so many that you'd ask anyone why they'd ever pick any other sorcerer type, but not so few as to not be enticing.
I'm also digging the really modular nature. So many options for one subclass.
I think it has its flavor, but I do not care for the bonus to damage based on CON instead of CHA. Now I know that sorcerer gets CON saves but this just feels like to much for abilities for spells. I mean for Fire giant three spells get the bonus to damage, where a Dragon Sorcerer gets it for how many spells based on Dragon type.
Interesting selection of different abilities, and I like how the first and second subclass benefits synergize. Pretty cool. Extra spells are nice. The big thing I find, though, is how each giant has a different theme and different style of play.
Cloud giants are stealth-sorcerers. Set up some fog, use minor illusion to teleport through guards. That's spamming a half-misty step for free. Each of the bonus spells are also utility spells that will always be useful.
Fire giants are standard blasters, along with storm giants. Well, frost giants have some defensive THP generation and Hold Person, so its not quite blasty, but still nice set up for control options while keeping your butt alive. Always good. I'm unsure if Aggy's Armor is good long term, however, compared to Shield, Mage Armor, Mirror Image, etc. I tend to prefer evasion over tanking on a sorcerer.
Hill giant is... interesting. Its a good positioning ability - start off shoving your allies closer if you need the speed, or shoving enemies back. Great to combo with a Polearm Master. Great for a buffing bard play. Stone giant comes with some good abilities, some bad ones. Resistance isn't too great a spell, but the others are good, and free AC is always nice. I love druid terrain control.
The Bad -
The fire giant option feels worse off than a red dragon soul. At level 6, when you get the ability, you could cast fireball with +CHA damage to it, or if you get your hands on a Staff of Fire, that's adding Wall of Fire as well. No bonus to scorching rays, a favorite of mine. Sure, you get two new spells and one extra cantrip, as opposed to free mage armor (one free spell AND saved spell slot per day), but I'm not sure if its worth the trade off.
Storm Giant is likewise blasty, but focusing on three spells. A melee range cantrip (usually bad idea to get into melee), thunderwave (okay spell with poor damage scaling), and gust of wind. ironically, there's a good chance that your Gust of Wind will push your enemies outside of your reach of the CON lightning damage. All in all, lackluster imho. I'd suggest Storm Sorcerer rather than this, to be honest.
Level 14 ability ... its Tenser's Transformation in a subclass that can't fight. At best, we have the Hill Giant using Shillegeah. Just.. no for the rest. Most of the other giant options don't even want to be anywhere towards melee. The level 18 feature is just doubling down on the level 14 ability, something that I can't seem to want to do in the first place. Also, more CON, but we don't need to charge into melee with a faux-barbarian that should be hanging back and casting spells. Well, I mainly play levels 1-10, so that last paragraph doesn't bother me too much, I just can't see a use for it even if I'd gotten it at lower levels. Probably end up like the advice for bladesinger - use it to enhance suitability while doing normal sorcerer magic.
I love the idea of this subclass first off. Giving the Goliath a reason to become a sorcerer and use that Con bonus. Same can be said for races like Dwarves, half orcs and other races typically used for melee classes. The idea of a Goliath starting of as a fighter or barbarian in his tribe, then as he adventures, he starts to learn how to channel that inner giant is a really cool character dynamic.
As interesting and exciting as the class is. It's not without its faults. The first one that I thought of the issue of size class. With the enlarge / reduce spell in effect and once you use the "Fall of Osteria" ability twice due to the "All father's blessing" feature, you can quickly climb a ladder. In this edition, there are 3 size classes above the race average of Medium: Large, huge and gargantuan. With these series of enhancements and only two levels into fighter, maybe learning spells that are only buffs, a gargantuan pc is terrifying. Ancient Dragons can be grappled, but without a powerful magic item, like a belt of giants strength, we got a gargantuan creature with a max strength of 20. Although, each attack with a melee weapon would gain a huge bonus of a potential +5(con mod) +5(con mod again) +5 (strength) + 1d4(enlarge) to damage. Mixed with a great sword it's 2d6 + 1d4 + 15. That's a max damage output of 31slashing on a swing. Which dispite the fantastic bonuses, you only get one swing as a sorcerer. The kind of high level play that you would be dealing with at this point makes that damage pretty insignificant.
It's also a subclass that could rely on high stats. If we're trying to make a melee-able sorcerer, it's going to need to desperately have 3 high stats, the CHA and CON that the class already needs, and now STR or Dex. The skill point economy is pretty steep on this one. As said by a few other people here the appeal of the sorcerer is that you gain these bloodline abilities through yourself. Dragons are high con creatures, celestial are high wis or cha creatures. We let them be expressed through the person and their CHA stat. So there's no need to change that.
In conclusion, I like the idea, but it needs tweaking. If you want it to stand on its own, it needs bonus proficiencies with light armor and some simple weapons at least. There should probably be a cap on the size class scale, although in the time I wrote this, I'm thinking of how this can be a cool ant man build. Give it extra attacks, it can be with the "RoFO" feature. It would make the idea of a rage bearing giant pc who only gets one decent attack a lot less tragic. And lastly, loose the con mod dependency, to get the full use out of the class it currently needs 3 high stats; while the average class needs 2. Just letting the cha mod do amazing physical and magical things is what I love about sorcerer. That's about all I have on this right now. I'm excited to see future and updated versions!