A franchise QB is who we need to draft in the first round. We can pick up quality OL players in free agency, but the same cannot be said of a franchise QB.
And if we do draft only OL first, we will be good enough to go 8-8, but no farther. This will have us picking around spot 15 for the next few drafts - which will see us miss out on a Big Ben type and settle for a JP type (again).
And if you say a franchise QB would be killed behind a subpar line, this is why you have them sit and develop a year behind a veteran QB as the front office continues to improve the OL.