You can make that assumption, but we havnt seen what culpepper could do without moss or the downgraded line yet. He was never healthy, he never played except with a knee injury.
You say that he should be playing decent. With a sprained MCL (preseason injury) he should not have been playing period. It was because he got that contract that he put himself in there. He was trying to play to justify the organization spending that much money on him.
At that point Mike Tice should have pulled him to keep his Quarterback from getting a serious injury, and give the team the best shot.
We will have to wait till next year to pass judgement on the Post Moss era, and if Culpepper is a real quarterback.