[Orgmode] org priority cycling - removing priorities

[Rick Moynihan]

Every now and then I find myself mispressing SHIFT-up/SHIFT-down on an 
outline and assigning a priority to it.  This then often leads me to 
navigating the point to the priority to delete it manually.

It would be great if SHIFT-up/SHIFT-down would cycle through:

[#A]
[#B]
[#C]
_ - blank (i.e. no priority).

This way I could easily undo the operation with the same keys.  Is there 
any good reason not to have this behaviour?

R.