Something like this sounds like a very cool idea, but as far as I know, adding new server regions isn't as simple and straightforward, as we would like it to be. There is quite a lot of matchmaking, server optimisation and connections going on in the background to make the current 3 regions possible (also, believe me, 3 regions ain't bad, since some servers often offer just one region) and adding new ones isn't that simple. It's also connected with renting and maintaining all new servers to provide hosting for the region.
Anyway as said I still think it's a very nice suggestion and I know that it would help players from different regions of the world to play without bigger problems.