It's not that they were fired or he left; the reasoning for removing start-up and stop animations when walking/running is that it creates a delay, though slight, for things such as ability inputs and the like. Yoshida said it would adversely affect combat because you're basically getting caught in an animation lock. (Think DRG-lock during jumps)
However, it didn't affect 1.0 even remotely according to friends I've talked to that did end-game content, such as Ifrit and Garuda. I just think that, with the way fights in this game require more movement than actual strategy, putting these animations back in would be a detriment.
I don't know if it could be made to where you can just move again during each animation to cancel out of them, but it would be great if they could do that.
