There's really no reason why the O-Line can't be better than it has ever been outside of potential injuries and/or Witten perhaps slowing down more than we think (TE blocking is a big key to this offense).
If Cooper is the LG and Collins is the RT, we essentially have 5 former 1st round talents on the O-Line (Collins was a UDFA due to an unfortunate situation of no fault of his own).
The media loves to stir Cowboys fans up, so now that Free is gone they want to make him a player that we'll miss out on. When Free was with the team, they couldn't help but say how bad he was. The truth lies more in the middle..he was a pretty good run blocker that could be a great run blocker at times and a capable pass protector that would have his struggles about 3 times a year. There were certainly better RT's out there and Collins is just far more gifted that Free ever was.
Cooper is a different story and Leary was underappreciated around the league. However, he was a decent run blocker and good in pass protection. Cooper has more talent than Leary did and was traded by Arizona because of injuries and the chance to pick up Chandler Jones. The Pats cut Cooper due to those injuries and because Cooper was rusty and wasn't starting for the Browns, his agent asked the Browns to cut him.
And when Chaz Green stepped in for Tyron last year, the O-Line didn't miss a beat.
Combine that with EE's great blocking we should be able to pick up any slack from Collins making the adjustment to RT. That's why I see Cooper and the LG position being more critical, but if Cooper can return to his old form and Collins can adjust to RT, it's a bit scary how good this O-Line could be. The liability of 'bad Doug Free' for those few games could be gone along with Collins being a bigger force at RT. And with Cooper we have a better fit for the zone blocking scheme and when they call for him to pull. So now we could be very strong threats to run right or left or up the middle and we can pull either guard or either tackle quite effectively.
YR