Funny how the assumption by some is that an Allardyce or Dyche type appointment is the "safest" option. There are no guarantees with any of these "survivalist" managers. For example, just because Big Sam has dragged a few sinking clubs out of the mire does not make him any less of a gamble than bringing in some big name top tier appointment who might bring with him a stronger, long term solution.
As for the idea that Tuchel has rejected us on the basis of there being a DOF, this seems like nonsense. If he is the manager people say he is, and Moshiri really wants him in place, then all parties would make it work. It will be the same situation with whoever is to come on board, that is, dealing with Walsh and, more importantly, the board. It is more than likely that dealing with the latter would be the biggest hurdle.