Weeden started the Cardinals game down two starting offensive lineman, with a hobbled Dez Bryant, and absolutely no help from Murray who decided not to show up that day. All this against what ended up being the 5th ranked defense in the league.
Not to mention a majority of fans were lauding Weeden the week before and claiming that we would have won the Washington game if he had stayed in the game.
I doubt Romo would have performed well against the Cardinals either. Our team was hobbled, it was one of those weird days, and we were due for a loss like that.
It's time to stop judging Weeden based on one loss. We'll be lucky to go .500 with any good backup. That's just the way the league is unless you happen to catch lightning in a bottle. The purpose of a backup is to get you through a couple of games until your starter can get healthy. Weeden is capable of that. If you're expecting your backup to come in and light it up like your starter, then they wouldn't be a backup.