It should also be Acknowledge here that they are better Educated then Sunnis in most cases and are more Urbanized people so its Natural to have Over representative at State and even at economic level.By power, I mean in government and organisation is their unity. While Sunnis are sub divided.
And if you want to take it other way then ever got info about Sippah e Muhammad ?
Sipah-e-Muhammad is just a small scale reactionary Group with very little or no Threat to anyone in Pakistan. Another thing is that they doesnt Target Average Sunni instead they mostly Target Sectarian Outfits while those of SSP types target average Shia as well.