Going back to the OP, having just one name, yet allowing for spaces in the name would help with this problem as well. This way, if you WANT a first/last name, you can. But if you really really REALLY want a single name that is an option as well.

The reason (i suspect) FFXIV gave first/last combos it is keeps from severely limiting the name options. For example, The Secret World has unique "nick"names.. in addition to your first/last. The nick-name is the /tell name. However, by offering unique names across a single server infrastructure, it has become increasingly difficult to find a viable name option. If games allowed for 'spaces' it would help remove some of this issue (without forcing a surname on the player-base)