This honestly feels as if what I might dislike least about the game and to me seems inconsequential in comparison to its greater failures. I honestly think infinite level cap is necessary for this system to "work"--all personal progression and individuality is collapsed into it and it would take forever to actually fill completely. It replaced skills (and Perks in the original sense effectively in my view) with a skill tree mechanic, and allowed other progression through workshops which interacted with skill access through Perks. On concept alone I guess I'm not even opposed, the *quality* of the "Perks" otoh. (and initial character creation just being vague numbers you can max to 10 anyway. I'm okay with limitless potential, Fallout already has a lot of explaining to in every game in terms of how on Earth a single person vs the whole world can be so immensely impactful--being a "perfect human specimen", maybe even eerily so and begging for hidden backstory, seems almost appropriate--but at least Traits and Tag Skills and flexible story/scenario writing gave you some individuality for an open world RPG.)
What bothered me, as the sole system your character developed outside equipment, was their implausibility. e.g.: Breathing underwater without mutation or technological assistance (some crumby makeshift explanation for them would have sufficed in the Fallout world--I mean, what on earth actually are these overpowered light refraction supertools called Stealth Boys in the first place? At least they're clunkier this time around, I guess. How can you carry so much shit without even a backpack that also has a bizarre physics bending mass-compression or interdimensional storage function that was a strange happy-accident byproduct of ridiculous pre-war nuclear research? Etc. Etc.)
I don't care too much about becoming overpowered and balance in the game, it's just where things are stupid. Honestly, that's why I "look forward" to Survival--nothing should be very "survivable" in this game. You shouldn't even be able to survive terrible wounds unless it's implied you have some mutation allowing it, or on downing/death there is a chance of random encounter of being rescued like how New Vegas started. If you are injured you should also be very vulnerable to scavenger wildlife spawning and finishing you off to the point where it's already been 99% likely game over already and should already have gone back a save, but hey, you didn't know that yet. Learning experience.
Speaking of "experience", why don't you get XP on a limited per-NPC basis for fleeing, losing them, staying undetected? Sigh. I could go on forever on what has probably already been said.
Some perks should be PipBoy mods on a workbench or bestowed by NPCs. It should be explained how your character even interacts with their PipBoy or whatever does it to produce VATS and detailed self-diagnostics. Do Vault Dwellers have special experimental cybernetics? Faint light producing pixel arrays back in the eye overlaying the retina based on pre-war experiments with foreign technologies which may have not been so stubbornly cumbersome and inefficient? Bizarrely an id post-apoc shooter Rage which Bethesda incidentally holds the IP of filled in holes wrt stuff like this better when it came to "Ark people" who similarly emerged from shelters.
Some Perks should be time spent learning through books, other research, NPC contact, IMPLANTED MEMORIES, anything...
Honestly a lot of this game is bad. It's more maddening because similar systems have been used before and not so shoddily, but not that many--most games are terrible, or at least I miss the good ones.
I guess on the concept of level caps in general, I feel more broadly conflicted with the idea that you are gaining anything at all from trauma where most people would progressively lose capacities. I don't get these games, which is pretty much every game (except hints of it like panicking in ufo/x-com), where you can hold it together through trauma like it's all physical, brief pain grunts or yells or being crippled doesn't cover it when you should be sobbing in pain and fear, and enemies alike, who should sometimes get to you and make you uncertain and conflicted in their dying moments. I'm not sure if I agreed with a linear Karma system, but the horrors of the world and you being expected to make so many final decisions should have some sort of impact on you. I don't understand how in this game chem use is moralised and you have judgemental characters who judge you like it's optional. How are they even still around in such a world? You should have to maintain sanity through certain in[ter]ventions just like rest, or suffer a penality to xp gains, ability to perform complex tasks, to hold it together and sneak, etc. I mean they already have in-game chems implied they were for these sorts of things for everyday use. In extreme circumstances, they may as well be compulsory.
This concept of adrenaline in "survival" I really don't like. Isn't it just a "[Killstreak]/Bloodlust" thing? I agree humans like hurting each other, perhaps universally, but they usually don't last long through it. Maybe if you had a trait you chose at creation that implied you had a disposition that could allow for such an advantage this would make sense.
Anyway sorry for how broad this is, but it's just, yeah the least of the problems, and your whole character's individuality is condensed into the Level/Perk Tree. I guess being able to have everything eventually if you really do grind that much *is* a problem. I think it's more that some of the Perks are out of place, some maybe being personal equipment mods, installed cybernetics or advanced mutation, and some showing more the individuality shaping characteristics maybe better suited to what Traits were--you couldn't be unique in every single way.