For me, the main difference between animation under Katzenberg vs Iger is that Katzenberg actually believed Disney had the talent in house to pull off amazing standalone movies (Little Mermaid, Beauty and the Beast, Aladdin etc.) On the other hand, Iger simply bought out Pixar and put them in charge of Disney animation.
Another major difference is that, under Iger, it seems like there is a huge push for sequels and a "franchise" mentality. Sequels were largely looked down upon under Katzenberg, and were often relegated to their own direct-to-video division. I seem to recall when Lasseter took over, he swore the awful sequel machine would get shut down. But it appears instead, he's just moved them from the minor leagues and put them in the hands of the big boys.