TBH, A Lot of this Season's Problems are because of Keystones
In general, I think that back when masteries gave small stat boosts the game was more balanced, and the game didn't feel as stale from game to game. Yeah, the masteries did less, but there was SO many to choose from!! It was FUN to notice the small differences masteries like Arcane Blade and Inspiration gave. I get bored playing with the same masteries every single game.
Keystones provide a lot of free damage to champions, boosting the snowbally nature of this game, partly because they allowed for champs who normally build damage to build tankier (
). Also, certain keystones work really well into champions' kits like DFT for
or Grasp of the Undying for
, while some champions have no keystone that fits them well at all like
.