The revenue allocation argument requires a better understanding of how federal systems work and how the Pakistani system works.
Firstly the NFC has two parts, the first is how much money the federal govt compared to the provinces (since 2007 50-50 )and the second is how much is distributed between the provinces and how. So till 2007 only 35% of all revenue was distributed amongst the provinces. So whichever groups dominated the federal govt benefitted more.
Secondly no federal to provincial revenue distribution system in the world allocates according to population or revenue. The reasoning is simple, in the federal system the provinces are equal regardless of size, population or wealth. ThirdlyProvinces/ states join a federal system to be treated equally and not distinguished by population, size or wealth. That is why the key criteria in distribution is usually poverty.