Think they are trying to milk server transfers sadly, there's no other excuse for them not doing it until NOV.
My suspicion is less that, and more that their process for migration is so weak.
Unless they've improved on it, if someone on the server you're moving to so much as made a mule that shares your character's name, you'll have to change it. Could have been for a month in 2007, and it wouldn't change things.
When Pandemonium got merged with Asura, I'd say 30-40% of the people I knew had to change their names, possibly greater. At this point, it might be a 50/50 shot or worse. It makes being on the moved side of a merge pretty crappy, in some ways.
Not merging the servers yet gives returning players the greatest chance to actually find people they used to play with...on the slim chance that they actually come back for the finale and all.
That's also something that they should still be able to work on after November, since it's account management stuff not content. So, I'd imagine, that kind of development work has been sidelined for the time being as they push to get as much added to the game while they still can.