I've mostly,
mostly come around on these. I still have a few concerns. There are also problems that are not problems at all. But let me try to encapsulate all of that.
+Expertise & Inflating DCs
Here's the thing; if you're the kind of DM who feels the need to keep inflating DCs in order to keep PC's from succeeding at things,
and you think that that's bad for the game... just... stop doing that? I don't really understand this mindset at all. I can at least wrap my head around the adversarial arms race optimization treadmill; people seemed to generally enjoy that, and I'm not going to judge. But if you think that there's problem with inflating DCs but you're the one responsible for inflating them... don't. Let players who've made the investment have a win once in a while.
I'd like someone to name me an adventure that can ruined by a single skill check, whether easily made or not. The idea is absurd, right? Even Perception, that skill most accused of "game-breaking", isn't really. It may have to change how you handle traps or ambushes (and an encounter that is designed to only work if it is successfully an ambush is not a well-made encounter) but I have to wonder how many games that is fully breaking. Honestly as a DM I worry more about Insight than Perception, but that may be more on me and how I run my own games.
+But my traps!
Traps that PCs have no way of spotting in advance are not traps, they are an HP tax. I'm not necessarily against HP taxes, but why bother with the illusion that it's a thing the PCs could have prevented but really can't because you set the Passive Perception DC too high? It's basically arbitrary damage for the sake of damage. So why not use environmental hazards as your HP tax? Force adventurers to wade through a pool of scalding water or a patch of thorny brambles. Yes PCs have ways around those too, but then they get to be clever and find solutions and solve puzzles and feel like they accomplished things. Alternatively, you could make the Passive Perception check only notice clues of the trap's existence, but still force the players to figure it out from there. Or you could just say bees. Bees everywhere. Take 10 damage.
-Codifying "Skill Tricks"
I was actually just thinking about 3.5's Skill Ticks the other day, right before this UA dropped. I remember really liking them, but I also remember really liking 3.5, you know? There's a definite problem with putting an action that really anyone trained in the skill should be able to do into a feat. It means that without the feat, you can't do the action. And granted, a lot of these feats mitigate that by being a bit more specific about the action economy of the action granted (a lot of bonus actions, a few "one of your attacks" mixed in) that don't codify the action but simply the ease and speed at which you can do it. I like that. But there are some that don't bother with this. Performer is the worst offender by far, but there are others.
+Historian
I love this feature. @
doctorbadwolf has the right of it; it's yet another stealth Warlord ability. I've both played and DM'ed for PCs that would get a decent amount of mileage out of something like this. I can imagine a PC or group of PCs justifying the bonus as being extra-motivated to complete the task quickly so Professor Monotone will just. Shut. Up. Already. But then my groups tend to be a bit sillier than most.
+
BeesMagic. Magic Everywhere
Now for the elephant in the room. Hi, welcome to 5e, where everything is magic and magic is everything. Your revolution is over! Condolences! The martials lost! My advice is, do what the rangers did! Get some spells, sir! The martials will always lose, do you hear me Lebowski? THE MARTIALS WILL ALWAYS LOSE!
Ahem. I can appreciate and at least partially empathize with the pro-martial crowd, but the sad and unfortunate truth is that 5e has left them behind. In 5e magic suffuses everything. It's practically a part of the natural world, if not for the fact that it's defined as separate from that (of course there is also nature magic, so <shrug>). And everyone seems to have a little ability to do a little bit of magic (or at least the potential) to. And frankly, I love that about 5e. I can understand the idea of wanting a game where magic is rare and powerful and wondrous but that is not the fantasy world that 5e has chosen to represent. So in that context I don't really see a problem with Arcanist/Naturalist/Theologian at all.
If there is a problem, it's that these three skills (Arcana, Nature & Religion) are too broad. The skills cover knowledge both mundane and otherwise. But the way I see it is; these feats represent something more than simply knowledge base. They represent knowledge not only of the subject matter but of the practitioners as well, and their skills and gestures and rituals. That's why they grant the cantrips they do (the most basic magical tricks of their respective practitioners), plus the once-a-day 1st-level divination that represents the character momentarily transcending that knowledge and talent and focusing it into a single, simply magical effect. There's a ton of flavor there and I rather like it.
As for the specific problem with Theologian, I am seeing absolutely nothing in 5e SRD that says divine magic has to be granted by a deity or similar power. Cleric spells are as much up for grabs by the Magic Initiate feat as anyone else. If I recall my AD&D 2e lore only the highest-level spells were granted by deities themselves; mid-levels through intermediaries (angels and the like), and the lowest levels weren't "granted" at all so much as they represented skill and knowledge of traditions and rituals which... sounds like what being really good at the Religion skill does.
Now, if you want to grab the torches and pitchforks over Survivalist, I'll be right there with you.
-Survivalist
Alarm? Really? That's the best you could come up with? I'll just continue to echo here what I and others have said about this. Some trick about actually surviving would have been nice. Maybe some additional benefits for tracking? Dealing with extreme environmental hazards? Survival is an odd duck of a skill because it seems to be the one that's made redundant by class features, so I can appreciate how difficult this might have been, but
alarm? Really?