So I have an aging QB (16 seasons) who seems to be a logical candidates to be my last cut of the season to take the team down to 53.
QB Sutton ($9M cap this year, $27M cap next year), 5 more seasons of contract!! He is my best QB according to my weights, but he has no strength or speed left.
From a squad composition point of view, he is the logical cut, but from a cap point of view, too much cap space (6 years contract to a 15 season QB seems excessive imho, 50% retire probability)
My money pinching mentality says do not cut him, cut someone else, and next year if he retires he'll "only" leave a 20M cap hole (or so).

Personally I would just cut him provided you find/have a suitable replacement. You'll have to pay him that money anyways and you don't have a large number of players that will need extended next season. So just get it over with next year, and move on to a QB that will probably be just as effective.

I would sign one of Shawn Morrow, David Copeland, or Andrew Pharr. None are great options but all should be serviceable until you can find your franchise QB

Yep, cut him and try and find another veteran to give a 1-year contract to (no bonus). Then try and draft one next year.