Um, the older character had nothing to do with keeping the name in the 2010 or the 2011 mergers. It was a simple case of the host world characters get to keep their name while the imported ones would have to change just the same as a server transfer.

http://www.playonline.com/ff11us/pol...ews18111.shtml

Character Name:
In cases where a character with the same name already exists on the "Destination World," you may be required to change the name of your character. If this is necessary, your character name on the character selection screen before login will be displayed in yellow. Follow the onscreen instructions to complete the change.

So if you want Server merges to keep your name you best hope yours is chosen as the host world and not the imported one.