Brother, I love your unabashed opinions, and often find myself agreeing.
Personally, I'd try hard to resist robbing Tua of his mentor. IMHO, we have no other QB guru to groom Tua. I don't have a ton of confidence in Chan Gailey, and from all the reports I've seen the only one dropping knowledge in the QB room is always Fitz. Even Dan Marino had Don Strock in his ear helping him learn to play QB at the NFL level. Patrick Mahomes had the great Andy Reid holding his hand every step of the way like he has done with so many other good QB's.
IMHO, we need to protect Tua while he grows, and that means keeping him safe via OL and play calling, while re-tooling the offense to play to his strengths. Pair down the playbook, revise the play calling, whatever it takes to smooth his transition. And yes, keep him well supported by his mentor. My fear is that if we lose Fitzmagic ... we'll undercut Tua's development, which is a major goal of this entire season in my mind.