Idea ( excuse my english ): players controled NM. As a quest reward you obtain some kind of crystal that you and/or a full party can make you morph into an/many NM(s) that would also have ability related to your classes + NM own abilitys. You have a goal to reach , a destination for example. And other groups try to get you down before you reach the place. both group can get reward.
I think it would be fun to be a monster, a big NM and fight 3 full group for 30 mins. It would add something unique to the game, and being an NM would add some kind of end game goal. And the quest reward would kick ass. Plus I could see fit those kind of quest in the actual main story.
Would add pvp and NM contents too. New quest, end-game, originality and life to the world to see inteligent, dynamique monster fighting players or other monsters*
NM vs Groups and/or NM vs NM*
What do you think? Please help develop the idea if you like it