According to Cult of Mac, Itunes 11 Is Coming In September, Will Be Rewritten From The Ground Up.

If apple were going to release and iTunes 11 in september, wouldn’t make more sense to call it Icloud or iHub and ditch the iTunes name? It probably essentially be an iCloud client for your machine and an interface for syncing your devices and managing your media like it already is. The iTunes brand is way out of scope to what it really does and with the addition of iCloud in September, you think it might be ready for a revamp.

However, I get user issues regarding a new app rather than upgrading:

1. People are used to it
2. it might be confusing to switch,
3. If you start with iCloud app 1.0, how do you deal with the exisiting iTunes app?
4. What do people do with all the iTunes integration with other apps and such?

Apple has a great track record with user experience, migration and getting people used to new things that I think they could make this migration work, but it would be a difficult one.