I never understood the idea of "just promote Shula to keep the same offense." If it was that easy why not just promote the O line coach or any offensive coach for that matter if all we are looking for is a body to just call out the same plays?!. I heard Shula was never a great O coordinator anyway. I love how for once we are actually targeting the big fish like Jackson, Whis and a lesser extent Shurmur. Atleast we arent going about this the usual "avoid household name guys at all costs" Panther way and are looking to make a splash for once.
You bring up interesting points that caused me to consider a few other possibilities.
Rivera recently stated that he wished he had an experienced coach on the staff, which suggests that Shula is not on the radar.
Shula (QB coach) and Hue Jackson (OC) is not much of a change for Cam. Whiz would have a fit with a real QB, something he never really had in Arizona-except for an old, beat up veteran, one that he got to the Super Bowl.