To the guy who wrote in about Diablo server stuff.
I almost did the same thing myself, as the blizzard store didn't really point out there are seperate clients. Anyways, unlike what the guys are saying it's highly unlikely it'll change, as it would require a complete redesign of Battle.net and most of Blizzards modern games. It's even just strange that you have access to both as both WoW and SC2 actually restricts you to your region (I cannot play on US servers with my EU WoW account for instance). In fact, the game actually operates with 2 completely different accounts when you change servers, with seperate friendslists and achievements. Also if you try to log in to the Korean servers it will straight up say your account isn't authorized.
And ye, it's sorta bullshit, but it's the same shit they've been doing for a while now. Although as I said, be glad you even have access to both regions.