If you keep Bangladesh as part of Pakistan, the majority population will be Bengali. Of course, it's likely that the political and military elites will still be mostly Punjabi.
Can we get a leadership that is more accommodating to other ethnic groups ? I'm imagining that some kind of a long lasting rule by a Suharto-like figure which while still maintaining his tribe's dominance in the safe zone, but having many of his helpers from other ethnic groups from himself has made him to consider neglecting them and their kinds men as the last thing he would want to do, would going to ensure Pakistan's internal cohesivity better than OTL.....