I think 1 badass LT would make the biggest difference. We can't afford to get Sims hurt and our RB Room is deep but not sure they can get yards on their own. Bob Brown was a beast back in the day with a long NFL career. Or more recently Weigert or even Rimington so we could slide Scott out to Tackle. Heck more recent Tackles like Lyndon Murtha, Marcel Jones, Alex Lewis or Brenden Jaimes would make a huge difference for our OL.
If I was worried about Defense I'd say Suh, Lavonte David, Randy Gregory or maybe even Turd Alberts as he was a heck of a Pass Rusher who would thrive in this defense.