I think it goes without saying, a cross-server friends list (within your data center) that would allow you to group with friends on other servers for Duty Finder would greatly increase the enjoyment and sociability of this game. Not only that, but it would also allow players to befriend other people that they enjoyed playing with in a dungeon, raid, or frontline. It also provides players, who might be on a low populated server, another method of having players to group with.

Most of the time, dungeons are generally quiet because some players have the mentality "why talk or befriend these people in my group when I'm never going to group with them again?" However, with the ability to actually add these players to your friends list and group with them again would be a step in the right direction with making the game more sociable.

One of the big things about an MMORPG is that it fosters a unique medium of community and friendship that other games cannot. As we can observe in other popular MMORPGs, they offer this cross-server ability by simply adding the player's account name or gamer tag, rather than the character name.

Although this feature is not likely to be implemented anytime soon, I believe SE should really consider it down the road to make FFXIV feel like a real MMORPG.