He has a theme that’s three completely different outfits, with loose colour continuity, and sometimes in the same episode. Thats not a theme, it’s a weekend away suitcase. And he’s always ‘dressed for the occasion’ anyway.
The most Doctorish of the outfits (I.e. in keeping with the loose ‘Edwardian Gentleman’ anachronism that was more a staple of the classic series, but also echoes in the Moffat Era’) was done away with quickly, after the first photoshoots, and then the closest thing to a default we’ve seen in what, three episodes? (Ironically, I’ve skipped both Christmas specials and I believe he wears that in those)
And his hair changes every other episode sometimes. It’s like Kate Kestrel, except she only changed the colour. It’s a bit silly. And old, but not in a ‘he’s really an alien’ way, and more in a ‘the production team’s heads are a bit wobbly’ kind of way.
The Doctor always came under that Einstein/Steve Jobs style — ie. Always basically the same thing.
I dunno. Maybe they are thinking ‘Prince, but orange instead of purple’ or something. Except Prince looked more like a Doctor half the time.
