Newton is a tremendous physical specimen, 6'6" runs a 4.5 forty and that gets you very far in the spread offense in college. It does not get you very far when a 6' 5" 300lbs defensive tackle runs you down. The defenses in the NFL are too fast and too big for a running QB to survive. Running QBs be their very nature get less calls than pocket passers when it comes to roughing etc. (just ask Vick). Like any gimmick it may last for a while maybe even a year (see Vince Young) but sooner or later, like the wildcat, the NFL figures it out.
Now add to the fact that Newton has questionable work ethic and has never had to make a second read in a football game, and I say bring him on! Twice a year would be great. He is gong to cost someone a general manager career, the only question left is which GM is going to make the mistake????????