Clanned roles. I -can- play them, but I dislike the way that, even with the Byn, a clan will eat up SUCH a majority of your time and have SO many restrictions to things you can or cannot do. As an explorer type who plays when there's 3 other people on (usually who aren't in my clan) it is unbelievably frustrating to be relegated to being alone in the city. So I wind up either avoiding clans, looking for the few roles where I can still leave, or breaking the rules and doing it anyway.
Also, elves. I'm not big on pk or stealing from other pcs. I think it's all fine and good when other people do it, but would prefer to avoid it unless there's such IC circumstances as to make avoiding it something that would be a total break with character. As such, I tend to avoid elf roles.
Warriors. The extra doubleplusgood combat skills don't make up for the lack of utility skills. I've played 1 warrior that lived more than 4 hours. And meh. Give me a ranger or assassin instead. Decent combat with a shitload of utility trumps awesome combat with no utility for me any day. Perhaps if I had a really long lived gladiator pc it would be different but... it's not different now, heh.
Dwarves. I like to be flexible in pursuing different stuff. I tend to be dwarflike in thought patterns IRL, flitting from focus/obsession to focus/obsession without much break between. Getting stuck in that with bigger and harder to achieve stuff IC is just too much like being stuck in my own head.