Mobile applications for MMOs are certainly de rigeur these days, offering offline access to your characters, chat facilities, even scratch card games with prizes in the case of the Rift app shown above.
Guild and friendlist chat options is certainly a great feature for staying in touch with people and finding out what you’re missing. With a sub-less model that will likely use short-term events to draw people back in, having an app gives the players themselves one more communication channel to ‘rally the troops’, i.e. encourage players to come back. I do like the rich character detail of the WoW Armoury app, it’s like having an old fashioned RPG character sheet on your phone but with 3d models.
What could Arenanet add to these obvious features to give it a Guild Wars 2 twist though? Maybe a 2d side-scroller jumping puzzle or two…?