I’d agree with you, were it not for the fact that how a game feels to play not a gigantic part of game design.
Were developers not quite literally hiring behavioral psychologists to design compelling reward systems.
You can disagree all you want, but how a game system makes its players feel is important. It’s not a mere issue of ‘facts versus feelings’, as there are a lot of facts backing up the fact that how a player feels going into a game is valuable.
A reward system, in particular, should make the player feel rewarded - like they accomplished a thing and got a neat reward for it, no matter how minor. It doesn’t even have to be power-based, as many games have proven (even WoW to some extent) that players will be quite happy plugging away at a hard boss for cosmetics.
On that note, a little randomness is good - it keeps people coming back, and repeating content they mightn’t otherwise. Keeps those drops feeling special, out-of-reach without trivializing them completely…
… But when you introduce too much randomness, the sense of reward is replaced with that minor dopamine boost one gets from good luck. Going for a piece of gear is essentially replaced with the feeling you get when you find $10 under the couch cushions.
Both are good feelings, nobody with a brain would try and prove otherwise, but one is much less arbitrary than the other.
That’s the key issue: there’s so much RNG, that each individual drop is essentially meaningless. It’s more about what number you roll when it does drop. Will you get an item worth using, or just disenchant/scrap fodder? No way to tell!
tl;dr: A little randomness is good, and it does make the game more fun; currently there’s simply way, way too much.
