I don’t get the impression he sees himself as above Doctor Who. He’s got that Netflix/GoT/Marvel money, and is surely very in demand. He wouldn’t do the various conventions if he didn’t like meeting fans and being associated with the show. I’m sure he’s said before he regretted leaving when he did and wished to have stayed on another year.
I also read somewhere that he’d never seen the show before being cast, and ended up getting so into it he was writing fanfic?
I think his stance just firmly in the middle of Tennant’s (would return at the drop of a hat), and Capaldi’s (feels his character arc is complete and returning would take away from it). He’s keeping the door open for one day, but there’s no need for him to come back to a franchise that would have him any time with open arms when right now he’s a genuine big name.
This is all my imagination. I’ve got no clue how he really feels of course. He played a brilliant Doctor though. Hands down my favourite.