Firstly, I want to state I am nonplussed by the effective skipping of the Rogue. I haven't really heard many complaints about them, and they seem to be the most popular class over all, and have a few splat subclasses, so I guess they are in a good enough spot to begin with. But really, the only thing they thought up for them in this cycle was a different flavor of an idea they came up with for Fighters first?
Favored Soul
Return of the godchild.
Divine Magic
Well, it's not adding more spells to the Sorcerer like Chosen of the Gods did. But it draws from a much larger pool than a single domain does, so that's a trade-off. I've never been a fan of how the Sorcerer has an arbitrarily smaller spell list than the Wizard to pick from to begin with, so anything that alleviates that problem while keeping them different is OK. I do wish they kept the Domain spell aspect in some fashion though, there were a few fun spells you could have could have poached from the Druid spell list that way (like Faerie Fire). Another potential benefit to this method is you can select Cleric Cantrips, Sacred Flame, in particular, is a very nice addition to the Sorcerers damage array.
Considering the other options at this level, it's much more interesting than talking to things, gaining proficiency in armor/weapons, and more controlled than Wild Magic. (Though I am a fan of the Wild Mage)
Supernatural Resilience
Half as powerful as the Draconic Variant. HOWEVER, the Favored Soul gets another level 1 ability to make up for that.
Favored by the Gods
Once per rest you can add 2d4 to an attack roll or saving throw. This strikes me as far more reliable than Tides of Chaos, unless your DM is particularly generous with allowing Wild Magic. The two features combined place you halfway in-between the two PHB Origins. However the two combined still aren't as fun as being able to fly in short bursts.
Blessed Countenance
Expertise in Charisma checks. Also you gain an otherworldly appearance of angelic youth, beauty, kindness, or wrath. Which is sure to draw in the people who don't like the idea of growing scales on their character. Relatively weak compared to other options at this level, perhaps to make up for the extra power at level 1.
Divine Purity
What, no wings? I guess immunity to poison and disease is useful, but it's passive and boring compared to other origins.
Unearthly Recovery
Once per long rest you can heal up 101 hps, but only if you are below half health (and also have 20 con, which you may not have) This is a large number to be sure, you are more likely to get 81 hp out of it if you don't pump con at every opportunity. The large number is supposed to make you think the capstone is impressively dramatic, but I think I would rather have Second Wind in any game where short rests are normally paced out. Also, not quite as fun as exploding dice or the ability to fly.
Thoughts:
Heavily front loaded, I suppose the expended spell options are intended to make up for the boring abilities that it gets later on. Silence + Subtle Spell is an awesome combo to be sure. And it starts off as halfway in between the other PHB options, making it fill the role of the "Normal Sorcerer" that people have been clamoring for.
Really though, this should get flying, somewhere.
Phoenix Sorcery
The Pyromancer Pyromaniac who isn't also a Dragon. Not to be confused with the order from Harry Potter.
Ignite
This is basically a Bar Trick. But you could combine it with the Control Flames cantrip for RP I guess.
Mantle of Flame
Once per long rest you get a bunch of benefits that other Origins get passively at later levels. This should really happen more often, especially at later levels. Upgrading to once a short rest would be a good place to start with, with an at-will somewhere around t3.
Phoenix Spark
Saves you from going down once per long rest, also dealing damage to targets around you. This is way more flashy and impressive Unearthly Recovery. Stacks with Mantle of Flame, but also eats it, which just reinforces what I said earlier about making that ability happen more often.
Nourishing Fire
You heal yourself passively whenever you cast a spell that can deal fire damage. Not just spells that deal fire damage like Fire Ball, but also spells like Investiture of Flame, and potentially Absorb Elements. This can get really ridiculous once you remember that Sorcerers can get extra spells via their spell points.
Form of the Phoenix
A much needed upgrade to Mantle of Flame, which includes flight (kind of the sorcerers thing~)but Mantle of Flame still has the problem of being tied to a long rest.
Thoughts:
Mantle of Flame needs to happen more often. Nourishing Fire has the potential to be a problem. Other than those two problems, and the potential for a Player to be a repeat Arsonist (which they would have done without this Origin, to be fair), it's solid and safe.
Sea Sorcery
I wish this had come out before I started my Pirate themed adventure. As such, we have a Kenku who looks like a Parrot Storm Sorcerer who would have loved to have this option.
Soul of the Sea
Swim speed and breathing underwater. These abilities are notably common racial adaptations in 5e, but it's always good to have a class based source for people who want to play other races.
Curse of the Sea
Makes your cantrips more powerful at level 1. This, is unique, warlocks have to wait till level 2, and other classes have to wait until level 6ish until their cantrips get beefier. Technically it makes your cantrips provide a rider that ends when you hit the target with a non-cantrip, but you can just spam cantrips over and over to make the curse stick. However! this will necessitate either reprinting some cantrips or printing new cantrips in whatever book this Origin ends up in. In the PHB, only Ray of Frost and Shocking Grasp exploit the curse, while Gust, Frostbite, and Lighting Lure are the splat spells that would benefit from this.
Watery Defense
Resistance to fire damage (nice). And once per rest as a reaction you can negate some damage from weapons and run away from whatever hit you. This is really nice, it's like having shield on tap, without expending a spell slot.
Shifting Form
An interesting mobility option that allows you to pass through small gaps, and grants resistance to damage from OAs. It stacks completely with Watery Defense, allowing for the tactic of drawing a single OA from a weak enemy, resting it, taking less damage on top of that, getting some bonus movement, then worming your way past the more dangerous enemies without drawing another OA, and and finally dashing away if need be. This sorcerer is definitely one slippery fellow.
Water Soul
You gain immunity to extra crit damage, resistance to p/s/b damage (even magical weapons), and no longer have to eat drink or sleep. It's both fun and useful.
Thoughts
This Sorcerer doesn't fly, but it has suitably interesting alternatives to flight. This is my favorite out of the new options that this UA provides.
Stone Sorcery
The Dwarf Sorcerer.
Bonus Proficiencies
All weapons and shields, but no armor. Fortunately, you have other abilities to make up for the armor.
Metal Magic
A bunch of Paladin Buffs and Smites, letting you stack as much damage as possible on your melee attacks. An interesting approach, but this class is definitely going to want access to the Various Blade spells from the SCAG. And perhaps Shillelagh if they can get it from a feat or multiclassing.
Stone’s Durability
It's Draconic Resilience, combined with Unarmored Defense from the Barbarian. Also you can turn it off with an action if you don't want to look like a rock, which should appease player vanity.
Stone Aegis
Swordmage. Strait up Swordmage. Relatively strange option for the compatibly fragile Sorcerer chassis, even if it is beefed up to the durability of a Cleric. Also has a relatively complicated calculation for damage reduction that results in a piddling amount of hp saved for some reason, just going with CHA Mod+1 would have resulted in less of a headache and similar math. The Real draw here is extra damage on a reaction attack. Of note: It doesn't stack with the War Caster feat, something the Stone Sorcerer is going to want to pick up regardless. Also serves as an interesting, if dangerous, mobility option on a class that is known for them.
Stone’s Edge
Even more Extra Damage on your Spell attacks. Granted, it's only 10 damage, but it stacks with the Blade Spells, buff spells, and Smites (which scale with spell slot level) making this subclass deal ludicrous amounts of damage in one strike. Also works on other damage spells should you want to use them.
Earth Master’s Aegis
Extend's Stone Aegis (also a typo was here) to 3 targets, significantly ramping up the chance for you to use a Reaction Attack per turn.
Thoughts:
This is the Swordmage, well as much of a Swordmage you can have without marking. It makes the Rogues, Bladesingers, Blade Pact Warlocks, and Paladins Envious with the weapon prowess. But Barbarians and Fighters will probably just be amused by the mage who thinks they can survive in melee combat. Also it could stand to be renamed into the Steel or Iron Sorcerer.