I like a mobile qb. Makes the DC on the other side think about things like qb draws and option plays. Even with a good OL there are times when protection breaks down. The guy with good feet still has a shot at making something happen. We don't necessarily need a Pat White, but having a few designed qb run plays, like draws, the read option and the old fashioned pitch option just give the other guys something else to consider, even if they aren't a big part of your playbook.