Eisner leaving was 100% the best thing for the company at that time. No matter what is happening now or has happened since, it was not a mistake to remove him from his position.
Iger leaving will be the best thing for the company if/when he does go in 2018. I don't hate the man, I like some of the things that the company has done during his tenure, but ultimately we've seen the full scope of his ability as CEO and, personally, I don't think that it is enough to really build on the legacy he inherited..
Has he been a terrible chief executive? IMO no but then he also hasn't been what I was hoping for when Eisner went nor do I think he is what the company needs now. I think it is time for a change at the top, a change that I think needs to extend beyond simply replacing Iger as CEO, but a change doesn't necessarily mean that things will improve. With Staggs seemingly out of the running there really isn't an obvious successor and until there is it is difficult to know whether to feel optimistic about Disney's future post-Iger. I just hope that the right decision is made when the time comes.