I never liked the Henchmen idea. It just didn't stick with me. It seemed to encourage solo'ing and discourage group work, which I just didn't approve of. Not to mention, I don't think I should be responsible for controlling some sort of NPC, whether it be a pet or a "henchman," when playing an MMO. I feel that I should be obligated to the character I chose when I began, not the character that I chose and the 3 underlings that support him the best.
"Nice to meet you. I'm an assassin.... Whoops. I wasn't supposed to say that."