The problem with your comparison of Romo to Favre, Elway and Manning is that......All 3 ended up winning the big game before hangin' 'em up for good. Tony did not.
You can have 2 QBs throw for over 300 yds with 3 TDs and 2 ITs and consider one to have played well and the other to have choked. If the ITs come early there is still time to make up for it (and depending on where they took place they may only cause you a possession). However, it they come late in the game they can seal your fate. Romo was notorious for turning the ball over in the 4th quarter and in a way that often led to the other team scoring.