I am in the same position - minus the screen rotation stuff. Just updated to 2.1 and now Music Studio is unresponsive. Runs up, does its animation thing, opens a “tracks” window and is no longer touch responsive. I can drag down on the ipad calendar just fine, and drag up for the ipad dashboard just fine - but ‘music studio’ is unresponsive.
One interesting clue is that AudioBus “sources” can still control music studio (i.e. start and stop the loaded song). Note that I have subsequently uninstalled AudoBus thinking that might be the problem.
I have restarted the device and quit all apps.
HW/SW
IOS - 8.1.1 (and I do not want to upgrade)
RAM - 16GB (2GB free)
Model - mc979ll/a
What are my options? Minimum I would like to roll back to the previous version. I too have 5 or 6 years of music here and I don’t want to lose it.