http://ffxiclopedia.wikia.com/wiki/Trust
http://ffxiclopedia.wikia.com/wiki/Alter_Egos
I know it's weird to say it's an improvement to an MMORPG to give you bots you can use in place of actual other players (and I know the Adventuring Fellow has been around for years, but I always found that particular mechanic a bit too high maintenance), but holy hell does this solve so many problems with this game. I mean, they aren't perfect; the places I want to use them the most are almost all among the places they can't be used and I wish the mechanic for getting them to attack stuff didn't assume you were using a melee job, but this still makes so many things so much less awkward.
('Course, it's almost certain they introduced this because the dwindling player-base makes it difficult to form a party for anything anymore, but let's not dwell on that.)

Plus there's this:
http://ffxiclopedia.wikia.com/wiki/Rhapsodies_of_Vana%27diel
http://ffxiclopedia.wikia.com/wiki/Category%3ARhapsodies
A storyline that gives you a permanent increase in experience as you complete it? Hot damn. Of course, they're only doing it because it's the last bit of content to be released for the game ever, but still.

Other musings about my return to FFXI:
I went and made myself sad by participating in Besieged. Man, Besieged used to be this grand, epic spectacle that genuinely made you feel like you were fighting an intense battle with an invading army. Now it's just a handful of fighters brawling for a half hour. Oh well.

(Also, I have the strangest feeling that Rhapsodies of Vana'diel is going to end up advertising FFXIV in some way.)