The Cowboys have the 31st ranked run game in the NFL, a horrendous offensive line, and a sub par defense. Romo throws for nearly 5,000 yards this season and the Cowboys go 8-8.
What do you think the Cowboys record would be when you take away the 5,000 yard passer? This is a classic "grass isn't greener on the other side" situation. Yeah, Romo has been bad in elimination games. But the Cowboys wouldn't even be in elimination games without Romo, they would have been long eliminated by their 4-12. record. Take a look at the Cowboys the last 16 years when Romo isn't under center.
You want the Cowboys to have real, lasting improvement? Get rid of Jerry Jones. Getting rid of any one player will change nothing.