They can't wear any Charlotte Hornets uniform without purchasing the name & associated trademarks from Benson first, he'd still own them even if NO rebrands.
Also if they wanted to do this for the '13-'14 season, they'd need to have had a design submitted by now to the league; which I doubt has happened since New Orleans still owns all the rights.
For example, this season, the Pistons requested approval of an alternate uni design they won't actually wear until '13-'14. So the earliest we could do this market study would be the '14-15' season.
It's an interesting idea, though; Staying the Bobcats, with Hornets hardwood classics nights, but I think those who support the team regardless will continue supporting the team regardless, and those who prefer Hornets will still want a permanent switch. So I don't know if it makes sense to spend the money it would take to get the name & trademarks back unless they were making a more permanent change.