Full review of this UA.
Kender
You know what? I have only ever read a few Dragonlance books (the original trilogy as well as a few sequels and prequels), and I've never run or DMed for a table in the Dragonlance setting, so I've never experienced the full extent of the awfulness of this race in play, but from what I've heard and read from the books, it got pretty bad. And I absolutely support this change to the race. Getting rid of their Magical-Curse that mandates their kleptomania and replacing it with a Feywild-Magic that spontaneously generates random objects in their pockets a few times a day is 100% a change that I can get behind. And some of the items could be pretty useful in an adventuring day, and you get multiple uses every day. I really like the image of the party trying to scale a cliff or tie down a prisoner and having the party's Kender rifle through their pockets and pouches to check for a rope, especially having to use multiple uses before finally/possibly getting the right item, and then just standing there with a few extra random items that they just chuck over their shoulders or put back in their pockets.
That would be cool (but also would probably only be funny the first few times they do it, it could definitely get old really quickly). Maybe they should add a "Kender's Luck" racial feat that they can take later on that lets them choose the item that they want to pull out of their pockets once a day or something like that? I could definitely see different Kender characters of multiple different classes being interesting, like a Kender Bard that uses Vicious Mockery and Taunt on the same turn on different enemies in battle, or a Kender Genie Warlock that fills their extradimensional bottle home with random junk that they collect from their travels, or Kender Fey Wanderer Ranger that collects trophies from creatures that they hunt from both the Feywild and Material Plane.
I don't see any mechanical problems with this race and think that most of their thematic issues from previous editions have been basically solved through this UA. There definitely will be some older players that will complain about this change because there are always people that hate change for the sake of hating change (even if the change is objectively good), but I don't think that they will end up being a problem. WotC is well aware of the problems with the Kender in Dragonlance, and seem to be making the steps to fix them.
Lunar Magic Sorcerer
I love this subclass. It's awesome. I would love to play in a campaign with a Stars Druid, Twilight Cleric, Sun Soul Monk, and Lunar Magic Sorcerer all in the same adventuring party. It would be great theming and would work pretty well together mechanically. Now, onto the mechanics.
Moon Fire - This is fine. Most of it is pretty bland, besides the ability to target two creatures that are next to each other with it instead of just the usual one. It's cool, it's useful, and it's pretty balanced. Not much to say.
Lunar Embodiment - A bit different from the other Innate Sorcerer Spell Lists from Tasha's, but cool in its execution and theming. I think all of the spells work well for the different sub-subclasses, love the ability to swap your sub-subclass during a long rest, and the free castings of the spells every day is just the cherry on top of this ability. I really, really like this ability.
This could make for some funny "It's not a Phase, Mom! It's who I am!" moments for characters the New Moon Phase.
(Also, imagine an Eladrin character of this subclass. You get to choose both your Phase and your Season every long rest, allowing you to have 12 different combinations every day that you get to choose from. Winter-New-Moon for the extra-gloomy days, or Sun-Full-Moon for the happiest/angriest ones, for example.)
Lunar Boons - Awesome ability, will probably take up a bit more table-time than usual due to having to check the PHB every turn to see if the spell that you're using is of one of the two schools that you're attuned to at the moment of casting it. Getting free Careful or Transmuted Spell on Evard's Black Tentacles while in your New Moon Phase, or Distant/Extended/Subtle Spell on basically any spell in any Phase is just amazing.
Waxing and Waning - This is just a nice ability. I don't really have much to say about it.
Lunar Empowerment - This is really powerful; the Crescent Moon ability is probably the weakest, with Full Moon probably being the strongest (New Moon is still good, but more situational).
Lunar Phenomenon - Great capstone ability, especially love the synergy with Waxing and Waning (I love that this sort of "use the same bonus action to do two things" ability that started with the College of Creation Bard subclass is being included, I hope more abilities like this continue in future class/subclass features). I think that the New Moon feature is probably the strongest, with the invisibility, necrotic damage,
and speed reduction all being combined into one bonus action, but the others are good, too.
Overall, I love this subclass. I want to see more like it in the future, and definitely want to see this one officially published.
Onto the Backgrounds! I'm not going to cover both of them, because they're not that interesting (being backgrounds, after all). However, them granting a free feat at level 1 is really nice, I hope that this continues into the Core Rulebooks that are getting republished in 2024. Also, the "Knight of Solamnia" background that grants proficiency in weapon and armor is definitely something that I want to see more of in future printings of the rules. It would be an easy and effective way of moving the cultural proficiencies from race (Pre-Tasha's) to background.
Finally, the Feats!
Feat trees are back. Yay, I guess. They did kind-of exist in Strixhaven, but this is a bit more in-depth than the Strixhaven feats were, which were just testing the water for this kind of development. I hope to see more of this in the future, I think that this sort of Backgrounds-granting-feats-that-build-into-Feat-Trees could work really well for the Planescape Factions.
It's also interesting to see that these Spellcasting Initiate feats just grant a single cantrip, instead of the usual 2 granted by these types of spellcasting feats. I love seeing more usages for Hit Dice in the game. It's kind of like a mini-Bardic Inspiration that can be used in a Warlord-esque fashion in combat. Oh, and more "don't expend this resource unless is succeeds" mechanics is always appreciated (5e is finally taking more notes from 4e, thankfully). I especially love the Life Channel mechanic from Adept of the Black Robes feat, which is really strong. You could increase the damage of your spells a ton, which, while powerful, is really costly if you need to regain hit points during a short rest.
Overall, I really like this UA. I'm not the biggest fan of the Dragonlance setting or novels, but I can appreciate this translation to 5e's rules and the lore changes made to update towards a more modern viewpoint/culture. If/When this gets officially published, I hope that they get rid of Gully Dwarves. I don't think that they can be salvaged/rescued in any way, they're way too ableist. I can't wait to see what they do with Tinker Gnomes, too.