When he had the briefcase, you are right. The guy looked horrible. He was the generic, characterless, babyface midcarder that Creative threw out there to fill time every week on SD or Superstars, whether he had the briefcase or not. But had he not won MITB, would Creative had cared enough to turn him and utilize him to his full potential? Or would they have continued to book him as simple filler, and basically let him be Smackdown's Kofi Kingston?
This way, he had a shot.
I'm trying to find the link where it was reported that Hayes had him win because he thought Bryan could be Smackdown's big babyface alongside Orton that they so desperately needed, but as you know Hayes is an idiot. Plans changed and they did what they did.
Only two new main-eventers have been made recently without the help of MITB or RR. They caught lightning in a bottle with Punk (then let it out) and Smackdown actually had competent booking and made a star out of Mark Henry. Everyone else they've tried to push as more than just filler opposition (Miz, ADR, Sheamus, Bryan, Swagger, Kane, etc) has been because of the Royal Rumble or Money in the Bank. I wouldn't expect them to push Bryan any other way.