Since then he's been fine. He's not one of my top three Doctors - those I think remain Four, Nine and One in that order - but he is approachable, he is even vulnerable, he does manic!Doctor very well (as referenced by Neil Gaiman); I'm not sure that he does bleak!Doctor quite as well. Of course, this means that he appears more human than alien, which isn't how I like my Doctors, but obviously does appeal to the masses.
He's had some very good moments. I am glad that the dynamic with the three regular companions so far has been entirely different; one of the failings of Old Who (with honourable exceptions in the mid-Tom Baker era) was that they all tended to slot interchangeably into the same emotional space. New Who has avoided that, and Tennant should take a lot of the credit; Rose, Martha and Donna are much more distinct from each other in the way they relate to the Doctor than, say, Polly, Victoria and Zoe (even if Zoe remains one of my favorites), or even Tegan, Nyssa and Peri.
I choose those trios deliberately because in a lot of ways, Tennant has rooted his performance in Davison's, and Davison in turn rooted his in Troughton's. It's not just the glasses (which the Tenth Doctor explicitly tells the Fifth Doctor are a direct lift); it's the being human again after a much more alien version of the role, it's treating companions as friends rather than pets (to be crude about it), it's showing fear and dismay rather than instinctively going for inscrutability. I'm not always totally convinced that Tennant has thought through what he is doing on screen; but he is almost always great fun to watch.
And I have to give Tennant a great deal of credit for the way he has promoted the show into being in itself a major media event again. He is, of course, a fan himself of long standing, and had appeared as a Nazi guard, a UNIT commander, and a mad Scotsman in various Big Finish audios. But I have to admire the way in which he has now taken the role of the Doctor and made it his own as a public personality; I can't remember any of his predecessors being quite so visible, though perhaps Tom Baker and Pertwee, in the different media landscape of the Seventies, came close. By the time he leaves at the end of next year, he will have lasted longer (in the sense of first-to-last appearance as a regular) than anyone except those two as well. I think he will find it difficult to move on.
Having said that, like Troughton, he is a versatile actor, and like Davison he is leaving the role pretty early in his own career. So I don't imagine he lies awake at night worrying about what the future holds.
And we'll see at least one possible alternative Doctor tomorrow. Can't wait, myself!
Index of my last few days' Whoblogging: One | Two | Three | Four | Five | Six | Seven | Eight | Nine | Ten