MAYBE UNPOPULAR OPINION: I like keystones and think they should stay
The problem isn't the fact that there is keystones, just the strength of said keystones. I'd say fervor and thunderlords are in a good spot right now, but any of the others are way too overbearing or way too underwhelming. Warlords bloodlust for example gives adcs with vampiric scepter enough lifesteal to out burst an assassin. Bond of stone on the other hand doesn't provide enough damage reduction to stop full tank gragas from 100-0 ing a fed corki or something.
They just need some tweaking and in the above two mentioned, probably a rework.