So compared to a year whose stock has risen/fallen the most?

I'd have to put forward

Risen

Jason Plato - showed real maturity in title win
Tom Onslow-Cole - blew away Chilton in his own team
Gordon Shedden - faster than Neal, just a bit to inconsistent/unlucky
Andy Jordan - 2 wins after pretty disasterous 2009
Paul O'Neill - stepped up significantly this year

Fallen

Mat Jackson - disaster. 3 great years in Chevrolet & BMWs previous
James Nash - failed to show much of his 2009 form