The bottom line, I think, comes down to whether Bradford or any quarterback in this draft is rated high enough for the Rams to justify the selection. The Rams cannot reasonably take a quarterback first overall if they think that quarterback has no chance to become a good player.
One other point to consider: Having a quarterback drafted first overall could, in theory, buy time for a coaching staff on the theory that any coach should have time to develop the quarterback it drafted early. The Rams are going through an ownership change. The new owner might want to hire his own people. Perhaps the new owner would be more likely to keep the existing staff in place if that staff had drafted a quarterback to build around.
The Seahawks' situation comes to mind. I wonder if the organization would have made such sweeping changes if, say, quarterback Mark Sanchez had been the choice at No. 4 instead of linebacker Aaron Curry.
Every situation is different. Those are a few thoughts to consider.