I think Romo is a pretty good QB right now, not great, not very good, but solid.
Once he learns to read the coverages better pre-snap, and can try not to lock in on a target from the snap, he will be a very good QB, maybe even great. Not worried about his fumbles, not worried about his INTs at this point. That is stuff every QB has to learn and get experience with.
Seems to me he has heart, and is a solid leader of the offense regardless of his age and experience.
He can't make all of the throws well, but he is accurate with the ones he can make.
Romo seems to have the fans behind him (for his team) which is great. Forgiving and understanding that young QBs will make mistakes. He has mobility which is something the previous 2 Cowboys QBs did not have.
He also only has limited film on him for the defenses to study, an advantage at this point. I think this is a partial reason for such great early success. The more they learn the more they game plan to force QBs into situations they don't like. But at the same time he seems like a pretty smart guy who can adapt and grow.
Disclaimer: I feel pretty much the same way about Campbell. He has the same amount of upside.