I think Kate comes across very well, she's clearly trying to keep her feet on the ground, which is very difficult in the media spotlight; it's important that her family and friends remind her of who she is, not what the media thinks she is.
There's no doubt that the person we saw in the BB House was the real Kate. She is genuinely likeable, and has a positive attitude, that's why the public grew to like her.
I really do think she has the potential to go far, if she paces herself and doesn't turn into a prima donna.
Brian benefited from his relationships with Dean and Liz, precisely because they were so different to him.
Bare in mind that she spent much of her time in the BB House in a hostile environment, she lost allies and friends (Alison, Spencer, Sophie), and thus her bond with Jonny became too close and too comfortable.
She did not have an ally who counter-balanced her personality.
I think that Sunita, had she stayed, would have balanced Kate perfectly.
I don't find her boring, indeed, she is many ways one of the most interesting characters to enter the BB House. Bitching and slagging people off is not interesting to me as it clearly is to many other people.