One feature I would like to see if the ability to sync folders with MM iDisk. I have few folders that I use everyday and sometimes I need to access the files when I don't have my MBP with me. Furthermore, I can't use Back to My Mac because of how our university IT configures our network
The new default in Snow Leopard is to have the iDisk on your desktop and set to automatically sync like a watch folder.
Unfortunately, it's a very weak process and worse in effect than merely mounting the iDisk when you wish to copy to it.
For instance dumping files into a local (synced) iDisk completes in a few seconds (because it's local), and then takes however long it takes to sync to the cloud. Trouble is there is no way to know how long this sync will take and no progress bar or indicator of how far along the sync is. So you can't ever just throw stuff in there and be sure it will be synced to the cloud because it could take anywhere from a few minutes to days. You may be able to share the file later on, or access it from another computer, but you may not, and there is no way to tell.
I like MobileMe and think it's an excellent value, but it is still quite a bit behind the capabilities of other services at this point IMO. It could be so much more, and I think it will be, but Apple is sure taking the long slow gradual approach.
Personally I'd like to see them focus on the email part of it. It's still horrendously slow on anything but primo Internet connection and it's a confusing mess like most IMAP email services. If Apple could make IMAP email actually work like people think IMAP email works (before they actually use it and find out the horrible reality), it would put them ahead of the whole industry.
That's something I would pay even more a month for.