I am in favor of closing down an arena in off peak times. Simply because it will discorage the milk-runners who gravitate tword the under-populated arenas. I log on, one night to see 22 people on in the EW. "WOW!" I think, "Going to be some good fights in here tonight." Alas, as I enter the arena and look at the roster, I get a sinking feeling; 15 Knights, 5 Bishops, 3 Rooks(including me). Ten Knights are in the same squad. I won't bore you with the details of what that "squad" was doing, but you kind of get the idea of what they were up to.
Yes by all means close one of the arenas, but instead of the EW or MW arenas closing it should be one of the LW arenas. My thought on this is, if one of the LW arenas goes below [insert arbitrary number here] population it gets shut down, say a 5-10 min. timer.
"This arena does not meet the minimum population limit."
"This arena will close in X min."
You still have the other LW arena open plus EW, and MW. Nobody is inconvienienced or have to play in arena they don't like, except the people in the shutdown arena, and all they have to do is go to another arena. If the open LW arena is within say 5% (thats 95% full)of max occupancy or greater for say 2 hours, then the other LW arena opens and everything gets checked in another 2 hours.
