another thing i noticed wich can easily be fixed is the max viewable distance. you might have noticed, that at the far distances away from your arena, that it starts to disappear on the horizon, and reappear when you get closer. To fix this so you can always see everything, go to the map properties in worldcraft, and i think its under the skyname, or close to it, it says 'max viewable distance' and is set just over 4000. change that value to 10000, that should be enough for most maps. all that does is render the map further when you play. with bigger maps, you need to set that value higher. This isnt a really important issue for your map at the moment, because it only happens at the very edges, and most of the action is around the arena. but if you expand the size, you'll have to do that.
other than that its all good. maybe add a few more details in the side rooms like tables, and light sources(eg lamps, torches etc)