Anything that just comes out is going to be a little glitchy. The admins will work through those glitches if they're reported.

I imagine you're not the only one who is kind of annoyed about having to hunt down the mobs, I've heard other people mention it as well. I imagine once more arenas are released, like the default one perhaps, it might be less of an annoyance once there's a less 'mob searching' arena that people can choose to go to?

However it would be pretty interesting to see people's designs of what they would use as a Mob Arena. Kind of like the Chunk of the Month but on a more permanent basis.

I'm curious, would they be building it in creative single player? If so they'd need to get the save world to the admins. If they were doing it on the server it'd be hard for people to come up with all the materials that they would need for such a contest.

Woo, my idea was set into motion!