Innervate will almost never be played now, taking away one of Druid's strongest cards will hurt it a lot in wild and make it way harder to make Druid top tier in coming expansions. The cost 2 mana gain 4 mana crystals idea was way better, allowing you to avoid Druid's explosive starts in aggro.
I probably would have also nerfed Flappy Bird by 1 mana. That card makes arena so stupid sometimes and really hurts so many classes that can't deal with an early board.
FWA makes it so that PW is going to be probably low tier 1 high tier 2, and make it so that for the next few months control warrior is dead.