tank is not useless they tank, obviously.
getting a tank fractured is much better than getting cls or Jedi rey fractured. so that's why tank matters
in your team i wouldnt bother fracturing tarkin or krennic
palpatine could be worthwhile to fracture if i really want him not to get a single turn. fracturing vader also would be good.
or thrawn as well. oh you dont use thrawn ok dt then.
but i think i would generally fracture vader and kill palp, and then kill death, then the rest