If you play a character long enough, you will always dislike the looks, just because you got bored of it. I've been playing on my Monk for 12 monks now, and I don't like her looks at all, but I really don't mind, as it's only looks. If you enjoy starting a new character at the other hand (unlike me), there's no problem restarting, even though you lose all your customized weapons and armor.
Also, when restarting a character, you can always go for the Survivor title (unless you already have it on the character you're going to delete, which I doubt), so you don't restart just for looks