I think there was ample concern that he was trying to do exactly that. He had already facilitated the creation of Dreamworks, which for a time became a viable competitor in the field of animation (the biggest one they had ever faced thus far). He also burned bridges with Pixar, which was in the process of splitting off from Disney to become another independent studio before Iger bought them out. Disney animation would not have survived this. Eisner had no viable strategy to handle this creative loss and seemed uninterested in wanting to fix it (perhaps even unwilling to admit there was a problem).
The parks were also decaying under Eisner's watch. EPCOT was ruined beyond any hope of recovery in only a few short years starting in 1994. Disneyland had a string of safety related scandals that led to multiple guest deaths, and the dilapidated state of the park as a whole was quite well documented. California Adventure and Studios Paris were mostly considered massive disappointments, and Hong Kong DL was also for having nothing to do.
And on the executive level, remember that Eisner was the originator of the strategic planning group. We would never have gotten Bob Iger or any of the others in that circle without Eisner.
Part of me wonders what the company would be like today had he stayed on longer. If would learn ANY lessons from the fear of having his power stripped, but narrowly avoiding it. But I have to be realistic here, he did unfathomable damage before he left. I think "lighting the place on fire" isn't too far from the truth.
Given that the timing of everything going to hell with Frank Wells' death are so precisely coordinated, I have to assume he really was the glue that held everything together. He was seen as the "financial" guy (who you'd more often be against in the creative business world today), but he seems to deserve a lot more credit than that. Just as I believe Roy Disney deserves more credit than he often gets as well (not that Walt didn't deserve his share).