Being a Taiwanese myself, the reason I believe that they designed the game this way is that we (Taiwanese and Chinese too) are a very patient bunch of people, and we will grind if the game designs it to, unlike the Westerners (I am using this collectively to describe all US and EU players).
The best analogy would be this and WoW, which was developed by an US Company. The game approaches when it comes to grinding is vastly different (It takes several days to level a profession from level 1 to max level, while on RoM it takes FAR longer). A sign of this patience is that the first player to ever get all Achievements in WoW went to a Taiwanese player, not western, and one of the reasons why Westerners gets world firsts in raids is probably they had beta servers to practice, while Taiwanese also had a language barrier on Betas.
The company probably didn't see changing the style of the game depending on the location would see as 'fair', but if the game was designed in such a way that it was WoW like when it comes to grind, I'd reckon they'd start losing customers over here in Taiwan (which is probably their largest playerbase) because the players 'got bored'.
I don't play on Taiwanese servers, because I read and type English more comfortably than Chinese. Cultural clash is a big reason for the 'void' I think.