Makes sense. I understand about having an instant dislike for someone. Although I think you're the first I've heard about disliking Katy. I enjoyed her in the audio "The Wormery" very much. She makes a great Iris. However, I can certainly understand how her as a person would turn you off of the character of the third Doctor.

Perhaps if you tried a story with Liz (Inferno perhaps) or one with Sarah (NOT Planet of Spiders). Perhaps without Rose Jo there you might actually like the Doctor!