As the server does not let hostile mobs spawn in the overworld, most natural mob grinders don't work. As such I think that McMMO xp should be turned on for mob spawners. Combat levels aren't all that useful on the server but it is still nice to be able to level them up.
I would more so suggest the spawn rate in the nether to be enabled with exclusive mob grinders that are enabled with McMMO XP. I feel as if though (all) spawners could be abused too much.
