I would definatly work on developing this untill it comes out. This way you can kind of ride on the hype and generate some traffic then sell.
I've been offered mid $XXX for each the following domains. Though i'm sitting and planning on selling early next year.
360arena.com
360league.com
360rpg.com
360fps.com
I would appraise yours currently for low-mid $xxx ,
If developed to end user low-mid $x,xxx
-G