Most Russians that play to sell in-game items for real money , aka rmt, will play there on Red, and that's why I'm playing on Blue
None knows when its gonna be merged, but RED has way more players, so its worthy so play RED in case, merge will take some time to be done here.
Thats why you play Blue, less people = free spots = more mobs to grind = less pk from russians I see a lot of cons playing Red and a lot of pros playing Blue. They will get merged eventually, so no need to worry about empty server forever.