There are a lot of teams that would love to have Romo, but there are not 31 teams that would rather have Romo than who they have. There aren't 27 either. The Saints, Packers, Steelers, Patriots, Giants, Lions, Falcons, Texans and Colts (assuming Peyton is healthy) would all gladly stand pat, and the Chargers, Pats and Panthers probably feel that way as well. Obviously some fans/media might have their opinion that Romo might be better than some of those, but the point is that there are plenty of teams that wouldn't view Romo as a significant upgrade, if an upgrade at all.
That said, I want to restate my position that I think Romo is a quality QB, and that given the right circumstances is capable of winning a Super Bowl, but lets not overstate his value, and lets not hold him blameless for the teams shortcomings. There are a hell of a lot of good QB's out there, and a lot throwing up big stats (again, 10 4,000+ yard passers this year). Romo's stats are very good, but without the team results it's natural he is going to be viewed with a bit of suspicion.