Brandon Weeden is about 1000x worse than you seem to think he is though. I think they should do it. I don't think they will. The Browns don't actually have a ton of holes and Weeden made them much, much worse than they actually are.
A good QB elevates the talent around him. Can Flacco do that? I think so. Honestly, this should have been his second SB appearance. Possibly third. Each year, his WR's have dropped the ball in the AFC Championship, literally.