I get your point, but the problem doesn't end there. The population concentration and economic development is also skewed within the provinces. If we go on with this, the poorest of the areas in Baluchistan will never get anything since the population and economic growth is minimal there. Districts withing each province would want the same principle applied and major share of resources within a province would go to the most developed district while we need to spend more on the poorer districts.
Atleast we would be devolving power one stage down. In a provincial setup some districts might still get neglected but the current system means neglecting whole provinces (not a few districts). I think the number of affected people is more in the current setup than it would be in the provincial setup. Once provinces are given power, districts can then demand more autonomy for themselves. People in every district will have to work in order to prosper. In that way power and resources have a better chance of getting divided fairly. Atleast sense of deprivation will decrease.