Eyebrows copped it from most on here, but can anyone say things have been better in his absence? Sure, he bullied everyone in the league to get his own way, but he was more reluctant to make in-game rules on the fly, and he would have handled the Adam Goodes thing with a bit more clout.
As for four umpires, I'm fine with if it means that the best umpires can call multiple games, or extend their careers. But if you needed data surely you pencil in a bunch of rounds next year for a trial (ie, all teams experience it), with a view to full implementation in 2017.