I don't honestly see how anybody can trust Romo with a lead. I can't remember the exact stat-line, but when the team is up by a TD or less and has been in the lead for the majority of the game...his stat-line stinks in the last 10 minutes. If we are coming from behind, that's when he plays well.
So having a good defense would certainly help, but I still wouldn't trust him to hold a lead because he's blown leads with boneheaded decisions and bad throws before.
And to me, there was absolutely no reason to extend his contract to the extent Dallas did. I think there is a large fallacy that he's a 'young 34 years old.' When you get older, your body doesn't recover as quickly. Extending his contract and thinking he'll play well beyond 35 years old is just foolish.
I don't think Tony has been helped with the porous defense, questionable at best O-Line (they did have some good years) and I think Garrett was probably as bad of a coach for him as we could have ended up with. But, he's not an elite QB and he's made his fair share of bad mistakes that he has nobody to blame but himself.
YR