The way it works on any competent (i.e., every one but S-E) MMO is this:

Log on, servers are over capacity, go into a queue. Window pops up "We're sorry blah blah blah you are #4321 in the queue, estimated time til you can log on: 5 hours, 20 minutes" None of this "World is Full, Come Back When Your Psychic Powers let you know there is room."

And of course an idle/afk log out feature.

This is the BASICS, the stuff every one knows who has ever played any MMO at launch.

Next, communication. Yes Square Enix, you're sorry. I'm sorry, we're all sorry. I don't want to hear it. Instead what I would like to hear is "We will be deploying new servers in X days, and in Y days we will be providing free server transfers to less crowded servers. If that does not fix the problem then in Z days we will deploy more servers."