Well we have two dervish players in our guild, and I already did a "DoA run" (^^) with them.
I even did one with a guildie's assassin (he wanted the mallyx statue in his hall of monuments).
I don't consider a certain class "weak" or "strong", because I own several "hated professions" characters (I have an assassin, a mesmer, and my Paragon is never wanted when I want to pug with other people than my guildies ^^), and I know what it feels to be "rejected" if you're not playing the "holy trinity" (monk, ele, warrior), but I also know that the only thing that matters is the skill of the player, not the profession he's playing (I've played with some really awesome assassins and some really awful monks for example).
But I reckon that it may be hard to find a group, that's why I joined a friendly guild: I wanted to play with real people (I'm fed up of mhenlo and his friends ^^) and the only what to do that was to join a guild...because nobody wanted my paragon in his group
