"What do you think?"

I think you finally had a good idea!
Bear in mind, my definition of a good idea is one I think I might like.
Actually the old PSR8000 had this capability. You could arrange the factory styles inside the banks any way you wanted. Like the Roland chord sequencer thing, it was lost along the way somewhere.
Current Yamahas do have a bank for User voices of course, but not like you are suggesting. Good idea.
DonM