I also have the hang on Loop Browser problem, and I fixed it by using Time Machine and grabbing Logic 9 from August. I'm now going to try to update to 9.0.1 again and try the fix above.
Another questions: how do I get extra midi channels into VE Pro, beyond the 16 in the multi-instrument? In rewire they usually show up in the right pane browser, but they're not showing up for me for Vienna Ensemble. In Pro Tools they appeared automatically. Is there something obvious I'm missing?