The issue I take with it is their complete 180 on certain things they've said regarding balance. For example during the assassin reworks when they said assassins should have good burst possibly slightly delayed, mobility and escapes, but that giving them significant CC is problematic and can lead to no counterplay combos, Then they released quiyana w/ a low CD root that can be made auto-targeted, and an aoe CC ultimate that rivals Amumu's in terms of impact in a fight.
As far as being consistent w/ the assassin rework, Quiyana low CD mobility is ok, heck even low cd invis w/ brush Q is ok, But river Q (ESPECIALLY W/ the EQ autotargeting feature) and her ult just put her way over the top in terms of what an assassin should have in their kit.
Imo that is the best example I can give about riot's 180 on their design philosophy and seemingly not factoring in power budget into newer kits.