That fact that he did 1 year and hasn't really been in anything notable since.... and Tennant did 4 and has since done Hamlet, Single Father, multiple chat and quiz shows, (and that's just off the top of my head) says more about Eccleston's attitude to the role than the role itself.
Would I like to see him in a multiple Doctor episode? Sure! 9, 10 & 11 together (heck, 8, too) would be great, but I doubt he'd do it.