Lifthrasil: I stopped watching because of her three companions. I like Jodie Whitaker and she is a charming Doctor ... even if she is portrayed too inept at times. But the companions are just a boring, annoying bunch without much character depth. And yes, the writing sucks. Jodie is given bad scripts that you can only do so much with.
I did like Bradley Walsh's acting though. But ultimately three is simply too many companions to have long term without them being poorly developed- and that made them seem like they were picked solely to make sure that ethnic checkboxes were being ticked. Bill had more development in a third (?) of the episodes while being a far less jarring example of 'progressive' writing, and when Moffat's writing was clearly getting a bit tired overall. I can't even remember the names of the current (well, two are gone, now) companions.
It was the plotting that really got me though, I don't think a coherent plot is too much to demand even in what is supposed to be light entertainment, and Doctor Who mostly managed that over its history up until recently. I didn't stop watching wholesale, but it's very much background TV and no real worry if I miss it.
Same here. I liked her initially. She was cute and charming and funny. ... But then she turned full Mary Sue and got boring and annoying.
Clara would have been fine,
if they'd actually killed her off instead of having her jet off with Arya Stark.
Going back a long way now, but Adric was a fairly similar character archetype, and retroactively improved massively after contributing to the Chixulhub Crater precisely because of the type of character he was.