Well, on the Simon speculation, my 1st question is "Does He want the job?" not every coach is obsessed with 'moving up the ladder.' So, have to be sure he wants it.
Beyond that, my personal preference would be for someone from outside the program - and someone who is not a friend/crony/pal of Fleck. I want a new voice in the room with new perspectives.
granted, Fleck is still the HC and he has the ultimate say. But, considering some of the offensive issues on the team, I do not want a "yes-man" as the OC. I want someone who will - if necessary - challenge Fleck and keep Fleck's conservative nature from stifling the offensive potential.
It is ultimately not a choice of "run vs pass." It is a question of how do you balance the offense to get the best production out of both the run game and the passing game. that is where I think some new ideas might be helpful.