It is catch 22 situation, if they do an operation in north Waziristan they are going to raise the irk of Afghan Taliban caz Haqqqani network operates from there and effectively will kill there supply route, if they don't TTP will continue to have safe haven in Fata. Army is waiting for US withdrawal if it happens they think Taliban will come again to power and everything will be honkey dory but I don't foresee them going soon, even if there is minimal presence of US troops they will make sure that they r protected