I would rather see a skills challenge like they do for NBA all star weekend. Get the best QBs to do some throwing drills with moving targets. Have the linemen do some world's strongest man type challenges where they go against each other in a knockout tournament. The further they get into each round the more endurance will be important to them. Get a mechanical football thrower and have WRs do a skills challenge where they have to make it to certain spots of the field and get points for catching the ball, etc. These are all much lower impact activities than an actual game and you would get much higher player participation.