No, it's that the number of users has exceeded 5,000 is all. I suppose waiting for another week to expand the max capacity is just too much for some to handle.
Yeah, it IS pretty unreasonable for people to want to actually play the game they purchased.
I think it has a lot to do with time frames. Japan's timezone is pretty well offset from the US and other countries over there that play a lot of FFXIV are too. So when you're signing on, chances are it's off-peak time usually for those players. I created and played a JP world character for a couple of days as well, and it worked out great for a little while when the NA servers were inaccessible.
Pretty much this. The problem is that as NA/EU players started rolling on JP servers, their prime hours start to matter less and less because the game's infrastructure worldwide is wholly insufficient for the number of people that want to play the game at the same time.