Melee only servers are tiring. You get one big mash up, round ends. big mash up, round ends. Usually degrades into fist fights, chilling out typing, and occasionally fighting. You quickly get a sense of whose the best duelist(s) who will subsequently win all the rounds. Meaning, no fun for everyone on the other team because their just going instadie in that persons presence. So they go to battle. Where skill with a lightsaber isn't enough to singlehandedly win rounds. Horsys, ranged, and teamwork all conspire to balance the game.
Duel and Melee only servers just get boring after a while. Battle is more random, hence less boring. But then again, I haven't played for 2 weeks.