QB's are a strange animal when it comes to NFL transition. 2 seasons ago Collin Klein from Kansas St was nominated for the Hiezman and was never even drafted or signed for a tryout. As much as I hate Winston he is a big accurate pocket passer. He also runs an offence that requires him to make decisions on the field.
Marcus Mariota is not as accurate of a pocket passer and runs an almost mechanical offence. His decisions are usually already made before the ball is snapped, although his ability to throw the ball on the run is elite.
Can Mariota run a NFL style offence? I think so, one could argue that it's probably easier then the offence he is running. Can Jameis Winston? Yes, FSU runs a very NFL style offence so there is no assumptions.
Also Tampa Bay, FSU, the Florida thing.
You do make a great point about Ray Rice and the latest rash of NFL abuse.