The only problem with NPCs jumping is making pathing for it is hard as hell. Almost every jump in gaming done by NPCs is a scripted event and had animation crafted specifically for it.
Newer and smarter tech got some "dynamic AI" features. Crysis have dynamic AI for battles and such. They jump, take cover, crawl, you name it.
I think Skyrim will have something more dynamical than the Gamebryo-version you're implying.