If we push Tet up front more; Mik, Holroyd, Prior, Tet is not a bad set with Smith at 13.
One more high-quality addition gives us the flexibility to swap Prior or Tet back to 13 if needed, and gives cover for inevitable injuries.
Everyone else has said it too but we need a really strong ball carrier who can punch holes in the opposition. That would take a lot of pressure off the young players and hopefully allow a more even spread of the work, and lessen the risk of injuries.
At this stage in our development and title-winning ambition, I just do not see the point of any more senior squad-filler signings. We have some great young players at the club. We already have Austin, Myler, Donaldson, Thompson and maybe even Mellor without an obvious starting place next year.