Ok with regards to Photoshop - Photoshop users are amongst the most inflexible users I have ever come across if it doesn't work like Photoshop they are not interested.... There are also a number of existing users who are very used to the current bindings (including myself) which we do not wish to upset more than nessary...

Luckily there is a solution that works for everyone (at least as far as keybindings go)... It might be a little too much work to make it into 2.0 though....

1) Ask the user which set of bindings to use when the initial installation takes place. Options should be at least Gimp 2.0, Gimp 1.x, Photoshop...

2) Users should be able to save and load any preference sets while the gimp is running - They should be able to share other peoples preference sets and install them easily.
This allows for the user to
a) set up a different interface for different tasks, b) allow for co-workers to work on each others machines with the minimum amount of hassle.

This type of functionality has been available in quite a few commercial apps (Corel Draw, Photopaint, 3D Studio Max immediately come to mind) for some years now.