Franchising him would sacrifice present trade value to hedge against the future of our own franchise. With an aging quarterback, if the franchise makes that decision I would consider it an acceptable decision.
BB really does need to anticipate at least the possibility that 2017 is the last year for Brady. Even if it isn't, they have to prepare as if it might be, because with older players you just never do quite know.
Do I think that Brissett could take this franchise in a positive direction if Brady took a career ending hit in game 1? He seems like a smart hardworking kid, but my answer to the question is no, probably not. I think we need to give Brissett another year under Brady's wing before making him the primary backup, to let him work on increasing the accuracy of his arm and the speed of his decision making, and that means we need Garoppolo for 1 more season.
Alternatively if do we make a trade, the value we get back had better reflect the fact that we are taking a risk in trading him.