Just wondering why we are reverting the "tank meta"

First off, I put tank meta in "" because it wasn't really a tank meta. Tanks were just viable. Anyway, why are reverting all the good things League did in season 5? I mean, it was widely considered one of the best metas. Aside from a few issues, like Sej and initial cinderhulk release, the game didn't have too many broken champs. I'm just wondering why you want to transition back into a 1 shot burst meta that everyone who didn't play Lee Sin or Zed hated?