I think story based quests you should return to the NPC I like the NPC interactions and cutscenes. It what makes Final Fantasy special.
Leves reward you instantly and soon we will have delivery Moogles so maybe rewards could be mailed.

Voicechat no thanks I don't want an Xbox Live experience. Leave it third party.

As for mail I think they will add a mail alert similar to the NPC Linkshell alerts and you can click to summon the Mail Moggle.

The looking for party channel is a must and will cut down in shout spam.
I also want the Looking for party toggle and overhead icon to return from FFXI.