I was thinking wouldn't it be cool if there were a secret spell or set of spells? like you had to complete some missions (specific ones, without knowing which to ensure you do all). Another criteria could be that you had to have certain items (not a whole suit just certain key items to trigger the spell.) and then last but not least the spell would vary by the number of players you have with you at the time and what level they were.... (hence they could only work on instanced levels or duels).
