The concepts for the various outfits in Phobos are based on the various classes. Each class has an outfit, and at release that outfit will be the only outfit available to the player (plus a noble outfit for Noble Account players). Players will of course be able to customise outfit colours.
All players will start off with the citizen outfit.
The first promotion will result in the player becoming either a page or an apprentice. Characters who become pages will then use the page outfit, and apprentices will use the apprentice outfit.
One possibility is that all heads could be available for all outfits (so you will at least be able to choose your character's head). We also expect that a few new special outfits will be made available for players who have completed certain quests/world events. Some of you have been discussing microtransactions for outfits and outfit addons recently on our forums. We really like the idea of allowing players to customise their character using outfit addons in this way (e.g. hair, hats/helmets, weapons, etc.).
Any more views you might have on this are welcome. Importantly though, we don't want outfits or outfit addons to provide any ingame advantage.