Sometimes there is a big object such as a tree or well in the middle of a room -- something that takes a careful map editing session or moving the room's center to be away from the center of the radius. The latter is the way I usually solve this problem, (the problem of it looking a little weird when my character is 'standing' in the center of a tree ).
Because the off-center center solves this, the NoCenter room flag is not very imperative, but perhaps should be noted for later? This flag would over ride the positioning of characters to not allow the center of the radius to be used. So, perhaps from where the character enters the room from, they could gravitate toward the side of which exit they arrive from, (up, down and etc could be randomized if no better solution.) Anyway, just a minor aesthetic for sure. ,':-)