“ I think the show should have ended after Tom Baker left.”
It did, as far as I am concerned.
I wouldn’t have minded John Cleese after Tom Baker left. I would have continued watching. After him, John Lithgow, and any other of the starring casts of Buckeroo Bonzai or 3rd Rock from the Sun. They could fake the accent. Just my taste, but I think mine is a lot better than whoever has been in charge, since.