The thing that has always annoyed me about guildwars is how my character looks. Sometimes I really won't wanna play on Factions, but I end up doing it because on every other campaign necromancers are butt ugly. I suggest maybe unlockable appearances. Say, for every campaign you buy 3 more faces releveant to that campaign. Or hairstyles etc. Also, maybe Stoop/Muscle/Width being changeable. I really love the fact I can change my height, but I think sometimes a little more is needed.
Another one, Prefixes (is that the right word?). Things like naming my character "The" (Insert name) ,"Sir" or "Lord". I find when making my character be called "The Chosen one" for example it is quite an immersion breaker for some to say: "We really need your help with this, The Chosen One", the prefix option would make it so you could select and alternative name, so instead of the earlier example it would be; "We really need your help with this, Chosen one", yet you could still be refered to in full in other situations like; "I called on The Chosen One to help us, he should arrive soon..."
A

