Why revert the Rumble buffs?

He's in a really terrible spot right now. He's at 2nd to lowest winrate in top lane and has been bottom of the barrel for countless patches. He's also pretty unique in that his winrate basically never achieves even 50%. People who have played over 125 games with him do not even break 50% on average. His winrate is also horrid throughout any game length. Basically he is weak at all stages of the game and he desperately needed buffs. The shield buff was microscopic but was a good first step.

Why revert a buff on Rumble? I can't imagine someone thinking wow a .1 ap ratio buff on Rumble's shield makes him broken as hell we need to revert that.