It might be this inner feeling he has himself that is driving him away from Newey by taking Ferrari from Fernando Alonso, like Senna did to Prost at McLaren. I don't think Vettel has quite reached the great status like Jim Clark, Sir Stirling Moss, Ayrton Senna - the big league greats.
Fernando's fight to the title this year has been a tremendous effort of guile, consistency and being able to drive the car at 100% lap after lap. Vettel gets more rear downforce as Red Bull have improved and just like 2010 when he got better exhaust blown diffusers he overtakes his team mate in the standings the wins races easily.
Where's his defining moment - like Mansell and Piquet at Silverstone in 1987? He could get it yet, but the my mountain of F1 greatness is a little steeper than some people's perhaps?