On one hand, I'm not racist, and, perhaps many years ago, I would've welcomed any non-white Doctors with open arms. However, there are two things I think that is working against this guy being a good Doctor.
First,
who is Ncuti Gatwa?! Looking at
his IMDB page alone, he hasn't really appeared in much of anything, and his only magnum opus up to this point is
some (presumbably) low brow British sex comedy show that clearly wasn't good for British airwaves anyway, seeing how its streaming on Netflix instead. Everyone else that had played Doctor have had much longer experience in professional acting compared to this guy, who only started acting professionally in 2014 (and not having much theatre experience, either). Why not have a more professional non-white actor like Richard Ayoade or Idris Elba play the 14th doctor? Gatwa just comes off as a literal diversity hire to play the next doctor.
Second, the Whittaker era of Doctor Who has effectively sapped any sane man's confidence of the show being a quality product ever again. The Gatwa era therefore can only either be
slightly better than Whittaker, or
far worse than Whittaker.