"world" of warcraft and the regions that divide us

hey guys (this is repost from my official forums post, but i thought id post here too to see what the mmo-champ community thought)
the recent developments of cross realm zones and cross realm raiding, and the introduction of realid/battletags got me thinking -
why do we have the game divided into regions? eu, kr, us etc
I realise connection issues, ping and lag, time differences, and the language barrier may get in the way, but arent the oceanic servers based in the usa? those are pretty far away and arestill playable.

I didn't find the right solution from the Internet.

References:
http://www.mmo-champion.com/threads/1222...-that-divide-us

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