The region has had no names before so making a new one was always going to be difficult. NWFPs minorities are as native and in some cases more native than some of the Pakhtun tribes. 100 years ago Hindko for example was far more widespread.
One of the core parties that was involved in the renaming ANP is not liked by the non-Pakhtuns of the former NWFP because they keep going on about exploitation of Pakhtuns even though there are non-Pakhtun members. People from Hazara claim the Terbela Dam as theirs! They believe tehy should get maximum benfit from it as opposed to far away places in NWFP. The ANP does nt do much for non-pakhtun areas or even the south of Kohat belt.
Punjab and Sindhs names come from rivers so its never really been an ethnic name. Balochistan was made by the Brits and Pashtun nationalists dont actually accept the current provicial boundary.
The provinces need to be cut up even more so people stop using them as clubs to batter one another.