I think this whole renaming thing is a big blunder and there are many reasons why it should not be renamed on an ethnic basis. There is this whole assumption that the lands constituting NWFP was made specifically for Pakhtuns - wrong indeed. NWFP is an ethnically mixed province and its future name should reflect that or be renamed on a geographical line. Had NWFP historically been renamed Pakhtun-whatever then it would be different or had Pakhtuns been the native people of this province historically then it would have been fair.
The province should be renamed Abaseen - the father of the rivers - all of NWFP's rivers flow into the Indus known locally as Abaseen. It is also a river that flows through Indus Kohistan, divides Hazara division from Swat and then provides the eastern boundary of NWFP at most places.
The name also ties with Sindh - named after the Indus and the Punjab - the land of the 5 waters - There you go you have 3 provinces of a river/water theme.