My idea for renaming weapons
I assume that there will be things that will be performed only a few times (solving the Ultimate quest of the Power Crystal that kill everybody). A good idea is that when you solve such a quest, some part of your equipement (the ones you used to solve the quest, like your sword when you slay a uber-monster), will become \'legendary\'.
A legendary weapons are not forced to have better properties/stats than the normal weapon of the same type, but you can now rename it (or even change its skin) at a blacksmither.
When you have such a weapon, i think you are not going to call it \'Q#?sdf^\' because you know that only a few people in the whole world have such a weapon so you are really proud to say \'I have WorldSlayer, the Great Sword\' even if this sword is just a classic short sword.