If River Song can concentrate on a dress size and this is her second regeneration, why can’t the Doctor concentrate on becoming a ginger?
Woman Time Lords can control the way they will look when they regenerate, while male Time Lords cannot. This was established in Classic Who, when Romana regenerated.
Also, the Doctor wanting to be Ginger is not about the hair color. In Gallifrey, the only ones to have red hair were the people called Heroes which were beings who were time-sentient (meaning they could see all of the time at the same time). So I doubt they will ever make him ginger.
*Mom hands me phone to answer*
- Me: Hello?
- Telemarketer: Hello, is your mother home?
- Me: I have no mother.
- Her: Well can I speak to your father?
- Me: Yeah, which one?
- Her: Which one is home?
- Me: Well they're both home..but I don't think you want to talk to Carlos. He just went through a breakup with his boyfriend, Antonio.
- Her: Oh, so your fathers' names are Carlos and Antonio?
- Me: No, no! My fathers' names are Carlos and Mark.
- Her: So who's Antonio?
- Me: I just told you, Carlos's ex.
- Her: So Carlos was cheating?
- Me: Yes, but that's only because Mark was cheating with Edith, our neighbor.
- Her: So Carlos cheated only because Mark cheated?
- Me: No, he THOUGHT Mark was cheating.
- Her: So Mark wasn't cheating?
- Me: I never said that.
- Her: Yes, yes you did!
- Me: No I didn't.
- Her: Y-yes! You did!
- Me: Did what?
- Her: Y-you- Never mind have a nice day, goodbye.
Plot twist: The next companion is a normal girl/boy who only dies once in their lifetime and has no remarkable back story but he thinks they’re wonderful because they are human and the Doctor needs reminding that you don’t need to be a mystery to be remarkable.