Straw Hat Pirate
There's a few reasons I don't like what its become but here's a few.
1) It breaks cannon. They've messed the entire thing up since the 50th really when they came up with "the war doctor". They also removed the restrictions on the number of regenerations to cater for crappy writers which changed things as well. I still maintain that the last time her character appeared in Doctor Who he was played by a man. That was in 1986 though. He was running out of regenerations and so struck a deal with the timelords to go back in time and kill the Doctor thus earning more regenerations to not die. That could've been used really well but they just scrapped it.
2) I don't like the idea of pandering to the masses who don't actually watch it anyway. DC/Marvel do the same thing and now they're complaining that people aren't buying the comics as much, but I imagine the people asking for change aren't the ones reading them anyway. People say how the timelords are "gender-neutral" and don't really have a concept of gender because they can regenerate. The people of Galiffrey were never actually born with regeneration as an inherent trait and it was artificially created (originally reserved for the planet's leaders) so they did have a concept of gender and you got male and female timelords. Regeneration did not change gender (except once by accident in the initial testing apparently). They could've changed gender by doing it that way but instead they just scrapped everything beforehand.
3) This is just a theory but why are there three companions? It's not like there hasn't been before (with one of them being a female timelord) but look at the actors they chose. First a white female Doctor. Okay, now a male companion. Make it a black companion, that's fine. But then there are no asian people in it. So we get an asian companion, okay....make her a female so there's not too many men....but this leaves more women than men? They'll get bad press for that so have they have another male. Ah, no old people so they get an older white man. I'd be fine with either of those companions, its just the fact they had to get all of them and in my opinion to appease the Twitter masses. I doubt it'll be long until some idiot wanting to cause a ruckus declares that its racist against chinese people - things like that happen. And if it does no doubt they'll do something about it.
There were a lot of complaints about Capalidi's first outing saying he was too old and the series felt too 70's. They catered for that by taking him out of his original costume (clearly influenced by the third doctor) and putting him in a black hoodie with his sonic shades to get down with the kids. The electric guitar was a bit much.
My main problem isn't that the doctor is female, but rather that it rejects the things that came before it and implies that they never actually happened.
Again, I'm not trying to offend anyone so feel free to ignore me please. And to prevent this turning into a massive argument which I'm sure Rui and Teapot won't be happy about, I'll not respond to any replies to this message. Sorry if you're not happy with what I've said but I'll leave it here.