They could go to a more modern standard of a mmo and have a given name and a surname.

Example:
My current ign: Commanderkeen
New system ign: Commander Keen

A first name and last name. It's probably possible on their current version of the Spacetime Engine. I don't know the exact limit of the characters allowed in a certain space but titles do have multiple words and are longer than most names currently ingame.

This would allow for couples to have the same last name in the Legends series and open up more of a verity to IGNs