I don't think Watford would be such a great career move. They tend to hover around mid-table at the moment and have a bit of a cash crisis at present.
Hull would present a better move, they have an ambitious chairman and have the structure in place to keep the club on the rise. Should really be challenging for the PO's in a couple of seasons, where Watford unless they have a major clear out will be expected to once again be mid-table.
But most people seem to be of the opinion that Sam is a bit of a gayer Dazzzza, and will not move north of ...errrrr....Watford!