I'm in a tiny guild of mostly real life friends. One guy (a warrior tank) who lives for pugging instances (he's done multiple in wrath so far, I've seen him in the first three, but not sure how many runs he's done). Apart from him, my multibox team is the only group actively running instances much right now. (I've run about 16-17 wrath instance runs, but won't both with TBC without a reason at this point.)

I've considered running Kara with the guild, but the question becomes...why? Kara gear is replaced very quickly by Wrath quest rewards. Apart from doing it to do it, that is. Or perhaps getting tanking gear - I've found one thing (a necklace I think) that is a tank item apart from blacksmithing created gear.

Same with ZA - I've debated pushing my guild to go run it (we never have, though I've been in a few times in the past), and I doubt we'd find much of anything worth getting.