How I, a Thoschei shipper, would fix the 14th Doctor problem.
So we all know Doctor Who wrote itself into a corner by retiring the 14th Doctor on Earth because now every time that something happens on Earth (which is the most common place for big stories to happen) someone will raise the question of why is he not getting involved, and the bigger the issue, specially if the current Doctor is not showing up (like in the war between the land and the sea), the harder it gets to justify it by him just being retired.
So if I could write the continuation of the story, I would bring the Master as the villain for the next special, like get him out of the tooth. He would regenerate on release and it would be John Simm because that is Tennant's Master, but he is after Dhawan!Master, like we see him regenerate and be weirded out and annoyed that he is stuck on Earth with this face again.
His come back would have both 14 and 16 coming to stop him. He would bi-generate at like, mid story, and I would explain that because the Time Lords are really dead this time, that's why the ones that are left are all bi-generating, it's kind of like their DNA trying to save the species.
Then I would divide the story with Simm!Master and 14 on one side and the new master and 16 on the other.
New Master and 16 would keep going with the Master's original plan and have the usual beef you expect from a Master/Doctor episode and end with the Doctor winning, as expected.
14 and Simm would have a completely different story. The Master is exhausted, all the rage and stuff left with his new regeneration and now he's just tired of everything that has been going on, he has been spiraling since the 13th Doctor era and he is now in rock bottom. 14 has had time to process everything that happened and he is ready to once again offer a hand, specially when both of them are hit with nostalgia over how things were last time they saw each other with these faces (The End Of Time). They also actually talk, and the Doctor finds out what happened to Missy, about the Lumiat and how the Master found out about the whole Timeless Child stuff. They make peace and the Doctor decides he has had his time to relax and get better and he is now going to give that to his best friend, so he takes the Master, the TARDIS and they leave to a different planet (idc which one, the Master just doesn't like Earth that much).
They're still retired but like this it explains why 14 is not getting involved every time the Earth is about to be destroyed. He's not on Earth and he still has a happy ending, he's not alone and he gets to save the person he has been trying to save for the longest time. Also the Master has blocked Earth news so 14 never knows what's going on and they live happily ever after while we still have other Doctor and Master to keep going at it through the stars forever.















