This right here is why potential needs to be scrapped. You are gimping yourself if you keep scrubs on your roster. anyone that isnt better than or does not have the potential to be better than my starters is either cut or used to fill roster spots.
I would like to see progression based mostly on player personality and how it fits in with coaches personality/skills and system being used. Just look at Albert Hanesworth. A few years ago he was one of the best DTs in the league, but being traded to a new coach and a new system just didnt jive with his personality. He is now pretty much worthless. The interaction between the coach and the player as well as the system they are in really effects how a player progresses.
Madden should let us set up positional philosophies, like Head Coach 09, that effect what the OVR we see is. Brady or Manning would have mediocre OVR at best with a Mobile QB philosophy(that you would want if you have a crappy OL or run the option), but would have great OVR with a Field General or Passer philosophy. it would have no effect on how they played just let us better set up our own systems.