He chose to leave. And he is polite to fans, but does no publicity for Dr. Who. Even the 50th anniversary he refused to participate, though I heard what they wanted him to do was pretty crappy anyway.I agree. He should've had another season at least.
I really did like Eccleston a lot and I loved his traveling companion, Rose.
It was the quality of the visuals I struggled with.
I would've liked to have seen him in the slicker looking Dr. Who productions instead of the bad H.R. Pufnstuf episodes.