I liked the modified Smith outfit a little better - it looked more like an eccentric older man's clothes than this, which screams "showman" almost as much as Colin Baker's clown suit. If modern tradition is followed, however, I'm guessing they'll give him some quirk like a fez or 3D glasses later on.
Or maybe the black's necessary to hide his colorful kidneys. Or he looks like a magician so we'll magically forget Mr. Moffat. Honestly, I'd like to see him replace those pants with a kilt for full-on formal Scottish look, but then you just know there'd be endless jokes about him wearing a skirt.