C2077 is the best adaptation of William Gibson's good novels on any visual medium. Unfortunately, it's got a lot of weaknesses as a computer game and as an RPG. The software is optimized for producing really dope looking walkthrough 'vertical slices' for marketing purposes. This is one of those games that most professional developers have nightmares about in that many of them say things like "it's never obvious right before a game comes out if it's going to be functional at all or really come together." In this case the answer was 'no.'
I think the perk trees were pretty professionally put together when you compare it to the average output for games like this. The bonuses generally work. There are separate talent trees for every weapon type and each has a unique identity. It's just that the combat encounters are not balanced. The game stops giving you on-level encounters at around level 30 or 35. If you over-level, the encounters become much less interesting. However, just leveling up -- unlike any game that takes Dungeons & Dragons as a guide -- does not mean that the types of encounters you have will change. In a D&D game, you fight different types of threats at every level range. In a game like this, you fight the same types of enemies at level 1 as you do at level 50. As many have noted, you could easily beat this game without spending a perk point on anything so long as you kept your gear updated.
The perks and stat system are functional, as in they would pass QA, but they are dysfunctional because the encounters are not balanced. It's set up on the assumption that there will be level scaling, but level scaling has a hard ceiling in the game so you wind up invulnerable to damage on the very hard difficulty with infinite healing items so long as you update your gear. It's a similar situation with the gear system. It would pass QA, but it's like Diablo 3's loot in which there are no legendary items, you cannot mass-deconstruct crappy items with one button, and you are constantly leveling up so your gear keeps getting outdated. In Diablo 3, leveling up to maximum is something that takes a few hours (or seconds with a boost). Most of your time playing is spent at the cap, with most gear just improving incrementally. Deconstructing loot is not that annoying because you can do it with a single button, and the looting system of rifts/greater rifts makes it so you don't pick up that many items anyway. In C2077 you have to manually deconstruct everything and every single enemy drops an item, almost all of which is better off sold or deconstructed.
Another odd thing is that in a scifi setting that has the potential for tons of enemy variation, a game like Division 2 has way more enemy variation with multiple drones, vehicle types, and enemy classes for multiple factions. At a minimum in Division 2, a faction will have medic, melee rusher, sniper, heavy weapons guy, heavy melee rusher, regular gunfighter, turret operator, and drone operator classes. There may actually be more enemy classes in that game that I'm not quite remembering. Some gangs also have unique enemy types as well, like flamethrower dudes. In that game each enemy faction also has unique expressions of each class type, which typically boils down to a unique ability or grenade of some kind. C2077 only has melee rusher, sniper, netrunner, and regular gunfighter classes. There are a small number of unique enemy types (mech, light flying drone, mechsuit cyberpsycho, and heavy flying drone) but all of them are quite rare, some of them appearing only once or twice in the entire game. For whatever reason, there are almost no netrunners in the game.
That also goes to show why CDPR are just muddled if they think an online C2077 can compete with games like Division 2 or Destiny 2. Both of those games get very lame if you play them for an extended period of time, but they just have much more content and much more refined systems than you would ever expect C2077 to develop. They might be able to have a competitive offering with it after multiple sequels to this and a decade of time -- which is just not going to happen.
An important thing that makes games like nu-DX and Dishonored work is inventory management. If you can only carry a few grenades, you have to make choices about when you use them. If you can carry hundreds of grenades, which in real life weigh 1-2 pounds and are tricky to handle, you have no reason not to spam the throw key. Even in Dishonored you can get away with spamming a lot of items, but you are still quite limited compared to a game in which you have infinite ammo cheats always enabled. Doom Eternal balances this by just putting most grenade items on a cooldown, which works for that game, but would be lame in an RPG.