Spellfire Review:
Lore: I barely know about Spellfire (Laeral Silverhand has it, right?), and I don't really care. This subclass is at least easier to reflavor to other settings. I could see this being used for a Silver Flame Sorcerer in Eberron or a maybe a pyromancer subclass connected with Phoenixes. The premise for this subclass is more interesting than the Moon Bard, but less interesting to me than the Genie Paladin or Winter Ranger.
Spellfire Burst: This weirdly incentivizes you to use sorcery points less often, as it's a free ability that triggers once a turn when you use sorcery points as part of your action or bonus action. So if you want to get the full potential of this ability, you need to limit your sorcery point usage to once on your turn. If you cast Heightened or Distant Counterspell you don't get the benefit of this ability. If you Quicken a leveled spell and then casting a Seeking cantrip, you only benefit from Spellfire Burst a single time. I don't really understand this. Is it really OP to give 1d4+CHA temporary hit points or deal 1d6 damage to two people in a turn? And triggering it on a reaction spell would be really cool and probably not too powerful. Imagine a spellcaster with low hit points casts a spell, so then you counterspell it preventing their action, and then deal enough damage to them to kill them. That could make for an amazing moment in a campaign, especially when combined with the later Absorb Spells.
Spellfire Spells: I'm still disappointed the new Sorcerer expanded spell lists dropped the ability from Tasha's to switch them out for spells of a certain school. That was really cool.
Anyways, all of the level 1 and 2 spells are good. Aura of Vitality is better than in 2014 and maybe it will be used more if you Quicken it, but it's not great. All of the other spells seem good.
Absorb Spells: Neat. Kind of sucks that this is your only level 6 ability.
Honed Spellfire: These buffs are pretty significant. Very nice.
Crown of Spellfire: Another demonstration that WotC does know how to design cool and interesting capstone abilities at least some of the time. Reducing damage by 5d6+18 without requiring a reaction is very nice. Flight is good, especially with hover. Magic Evasion is also very good.
A pretty solid subclass. I agree that it's kind of a replacement of my beloved Divine Soul Sorcerer, but it's pretty good. It could use some tweaks and maybe a short mention of how it could be used in other settings.
Bladesinger Review:
Lore: Mentions how it was started by elves, but how some non elves are also Bladesingers. Also everyone loves them. Cool.
Bladesong: No longer works with armor, but you use Intelligence for attack and damage rolls with weapons, and also you can use it an amount of times per long rest equal to your Intelligence modifier. Funny how they keep changing that last part. Bladework should probably just be a feature of the subclass instead of only active when you use this ability.
Training in War and Song: You get more weapon proficiencies and a few options for the skill proficiency. And you can use your weapon as a spellcasting focus. Pretty good, opening up the types of weapons you can use is good and broadens the archetype. Not every bladesinger needs to be the same and use a longsword.
Extra Attack: Mostly the same as before. My only complaint isn't about this subclass, it's the fact that they keep not giving this to other Gish subclasses! Why can't Armorers and Battle Smith Artificers use this!?!
Song of Defense: It is almost always better to just cast Shield or Absorb Elements instead of using this ability. Only situationally worth using. I've never liked this ability and would prefer for it to be replaced with something else.
Song of Victory: Pretty good, I guess. Definitely not going to be significant damage. Probably weaker than the original version, especially on dual wielding Bladesingers.
None of these changes excite me. I've always liked the idea of an arcane gish, but don't really like any implementation of it. Bladelock is the best execution, but doesn't have the flavor or abilities I'd prefer.
Overall this UA is filled with some pretty good hits (Knowledge Cleric, Genie Paladin, Dead Three Rogue) as well as some pretty big misses (PDK, Moon Bard). I like most of the ideas and mechanics, but some things need to be rethought. Pretty interesting getting 8 subclasses at once, this took a while to review. Hopefully we can get another UA version of some of these before the deadline for the book comes.