I think it's safe to say that Anet have every intention of keeping the "archtype" for the costumes. I mean, a caster is in light armor/robes/dresses, heavy dps is in plate armor and the light/squishy DPS types in leather/lamellar-ish armor.
Just look at some of the pictures that has been released. Too on the armor subject that they have touch on.
http://wiki.guildwars2.com/wiki/Armor#Armor
From what I can see, they intend to keep it in a both recognizable but too
very typical/stereotype fantasy setting that we have come to know. So yes, I very much think it will be kept within my ideas when it comes to customisation and will continue to do so.