Things tend to get cast into extremes with Romo...
He's not Brady, Manning, Aikman, Marino, or Elway, etc. But all of those guys were first round QBs, except for Brady. And Brady played in a power conference in college.
But IMO he's been a huge overachiever. UDFA, from a small school, he comes here and sits for years before getting his shot, and solidifies our QB position for a decade.
If your biggest gripe about him is that he's not going to win a championship, that's too binary for my thinking... If Russell Wilson, Kaepernick, Eli Manning, Roethlisberger, Matt Hasselbeck, Joe Flacco, Rex Grossman, Donovan McNabb, Jake Delhomme, Brad Johnson, Rich Gannon, Kerry Collins, and Trent Dilfer can get to and/or win a Super Bowl, there's no doubt in my mind that Romo has that kind of ability. Look at that list of guys... and then think about the coaches that got those guys to the Super Bowls and the defenses that those guys had helping them out.