When you put it that way, I have to agree. There isn't some magical OC that's going to come in and fix everything that needs fixing in one season.
Playbook: despite opinions to the contrary, the playbook remained the same. They tweaked it, simplified it, but the concepts were all part of the Patriots playbook. Are we limiting the search for an OC around keeping the playbook? That would be an odd concept.
So I agree, we need:
New OC, OL, QB coaches
New players: WR1, LT, RB2, TE2
New playbook?
We have two opposing forces:
1. Do we keep the playbook + QB and find an OC that will fit these constraints? If that's the case we're better off just promoting Caley.
2. Do we find a new OC that brings in new schemes revamping the playbook that the QB and skill players will need to learn?
I say yes. If we're keeping the QB as a long term investment, we've already seen how he performed w/ a good & bad OC with same playbook. The results were the same, failure.
Bring in a guy like Kittley who is 31 and can be both OC/QB coach to energize the offense. Find the right talented players to fit his system and the rest need to learn.