It does not matter where the power house is located the river Separates 2 regions - one a preodminantly pashtun area and the other a predominantly hindko speaking area. The Indus does not flow through a Pashtun area but acts as a division. The people of Hazara have little interest in joining a pashtun state where their language will be second class.
You can build the dams if the people further down stream agree - and that does not necessarily mean just the Sindhis but other Pashtun areas too.
What makes you think Pashtuns would have no white elephant? There will need to be some army and police and under independence it will be the americans who will influence which course it will take - judging by their choices in iraq and afghanistan they will opt for power crazy dictators.
Development is amjor issue all over Pakistan and sadly it is not just NWFP which is not developedto its potential but all the other regions too. pakistan is a country which could sustain itself very easily but the the problem lies with the people managing the country.
The reality is Sindh, Pashtunistan, Balochistan, Punjab or whatever there is youwill still have those same corrupt incompetent polticians and leaders.
When Pashtun areas both in Afghanistan and Pakistan are combined, they make 0.5 millions (5 lackh) square kilometers. Pashtuns are only 42 millions and most of this area is uninhabited...much of this land can be developed into agricultural land...In fact there are many crops, vegetables, and fruits in which Pashtun areas have competative advantage over others...Moreover, many rivers (e.g. Kabul, Helmand, Kunar, Swat, Panjkora, apart from many other small rivers) have their headwaters in Pashtun areas or flow through much of their course in these areas... and Pashtun areas are neither getting their share of water nor can utilize it...
As for Tarbella, the powerhouse is located in Sawabi...and much of the rivr bank at Tarbella is inhabited by Jaduns, Yousafzais, Mashwanis, (Sarikote, Ghazi, etc.)...
But Pashtun areas can themselves be converted into virtual power-houses ...the entire length of river Kabul right from the mountains of Mohamand Agency to Kabul provides dozens of sites for big and small dams ...similarly, in Kunar, Swat, Dir, and on river Helmand in Kandahar, Gahzni numorous power-generating facilities can be constructed...
Further, in Karak and southern districs, there are huge deposits of natural gas discovered...Besides, Tajakistan is keen to sell its electricity at a very cheap price to the neighbours...Moreover, Pashtuns can directly purcahse gas, oil from Middle East and Central Asia etc. ...that is why oil is three times cheaper in Afghanistan than in Pakistan...reason is Pakistan buys oil from international market and sells it three times the international price to people just to feed the army and meet its defense expenditure...Pashtuns wouldn't have the white elephant called Army(which is what makes Greater Baluchistan scenarios attarctive to big powers).
Anyhow, I am not saying Pashtuns should seperate but nationalistic sentiments ar really on the rise in Pashtuns especially in young people and ultimately, when they see Pakistan cannot or is not willing to bring normalcy and development to their areas but is rather using these areas to play geopolitics and divour billions of dollars, they may opt to walk out...especially when global and regional powers also have interest in it...