I used to feel like the dervish and frenzied berserker were both crazy, but now I don't feel as strongly about the dervish. I wouldn't disallow the samurai just because I feel like the class stinks, that's not really fair. If someone really felt like the samurai fit their concept, I would let them play one (and someone did, for a time), but I would (and have) encourage them to try one of the similar archetypes.