Trackwheel/Keyboard
 

Which is worse: loose trackwheel or loose keyboard?
Is either repairable without getting a new unit?

I don't think either one is easily replaced on the 8700. The keyboard is an integral part of the circuit board and the trackwheel is replaceable (I've seen them on promobility.com) but not by just anyone.

If you're careful, have a T6 driver and refer to the disassembly instructions you might be able to resolve the matter. However, I think you'll need replacement parts in either case. My loose keyboard was caused by broken plastic under the keyboard so I'm just dealing with it for now.