In general i am most excited about the party search function in 2.0 Allowing players to fill out their dungeon of choice and matching players from across servers is significant.

i think a companion system could be really helpful though. Solo play from battle related jobs could use a bit of propping up after everything that has been done in recent months. Allowing a player for example to call three companions and make a light party would be interesting. I don`t think a full party of companions would be a good idea, but a light party would be enough for exp grinding options and some moderate difficulty questing/missions.