I tried Wailing Caverns at 19 or 20 and it was HORRIBLE. I could single target dps, but if I AoE'ed and the jackasses would call for help and then wipe-ola.
That is because WC is idiotic. Druids that heal themself, put players to sleep for ~10 secs and run for help are bad for 5 boxers. I went to the deadmines because I hate WC so much.