How come the first Doctor actor quit after 1 year? Did he think the show sucked that bad?
I don't know. There have been many reasons given:
-He only wanted to be one series.
-He did not want to get typecast.
-He was overworked.

How come they added a pointless Black guy to the cast in season 2 - I really don't like that character.
He travels with the the Doctor in the 2nd series. He becomes braver and more useful.

Seems like the first Doctor was not at all Doctor-like and the second Doctor is a schizophrenic Which is also not at all Doctor-like.
Can you be a more specific.

The 10th Doctor is not schizophrenic.

The show would have been better if they had a competent casting director who was capable of casting Doctor-like actors to play the Doctor.
What do you consider "Doctor-like".