They've actually never released an MMO on a global scale to my knowledge. FFXI's release dates were different depending on both region and console...

JP May 16, 2002, PS2
JP November 7, 2002, Windows
NA October 28, 2003, Windows
NA March 23, 2004, PS2
EU September 17, 2004, Windows
NA April 18, 2006, 360
JP April 20, 2006, 360
EU April 21, 2006, 360

The only experience they have of an MMO launch on a grand scale is FFXIV 1.x, and they had a single datacenter for that launch, so this is still something new in a lot of ways.