Please, people who don't really know what they're saying should stop.

There always has a way to avoid each region prime time. They even have NA/EU/JP servers. Tell me why can't they separately do a maintenance?
What ever the reason is, customer has a right to complain about this. Because this is their job to handle, not us.

I had worked in business like this before, I know what the standard is. If you don't know then you're the one who should "just stop".
It's a lot easier to roll out an update to all the servers at the same time than to do them at seperate times. It also eliminates the possibiolity of some people being able to discover something or beat something long before other people even have a chance to log on to the game.