I don't think Cat does have a strategy, though. I think she's flown under the radar because of other people's assumptions about her, because she's so much younger and so much less famous than everyone else still in, rather than because of anything she's doing herself. (Or, if she's a fascinating character, she's being done a real disservice by the edit.)
I don't think Ruth was at all unpleasant. She was often discomfitingly direct, but that's her style of humour -- if you saw her on Uncloaked, you'll recognise she was doing the same thing with Ed (the joke about her unwell dog having died when she was in the castle). And she didn't like Jonathan Ross, and that stood out far more strongly in a programme where there's a lot more pussyfooting around and luvvyish complimenting 'I'm voting for you because you're so clever and would be an excellent traitor, darling!') than in the non-celebrity version. I think that her directness was regarded more harshly because she was a young woman, and also because she was Irish.
I agree that Alan's spite seems to be emerging more in the edit. He was hilariously off-kilter at the start, sweating and blurting and all of a dither, but weirdly, with the return of his confidence seems to have come a big helping of default bitchiness. Is this who is actually is, when not knocked off-balance?
Yes, I do wish Paloma and Niko had lasted longer, too.