Why I don't like 7-8 player games: That many people ruins the flow. You're sitting around not able to build for long periods of time, it's harder to trade than you would expect since people have several turns to get what they want randomly, and players often build 2 points a turn, making keeping track of leaders very hard. I suppose you could fix some of this with the build on everyone's turn rule usually used in 5-6 player games, but that just seeemed like an invitation to chaos. We figured if you have that many players, why not play two games, which we know is fun?
Why I don't like Cities & Knights: It's a pain to put together, it is perhaps the worst in the series for exacerbating the luck factor, and smacking the guy in last place just seems rude. We probably have the most hardcore Settlers players around here, and no one plays Cities & Knights.