I happen to agree with you... The debates will be extremely important, as well as the conventions. Obama is already a known product, the verdict is in, and he gets poor marks on the economy. No matter how beautiful of a speech he gets, it won't change how they feel about his stewardship of the economy. Romney stands more to gain and lose regarding the conventions, he is more of an unknown product, if he comes across as competent, he will gain a structural advantage of gaining some of those undecideds that disapprove of Obama.
So I believe the conventions are vitally important for Romney.