I personally would like to see a new style in nanos. Being my main character is a Doctor I've heard several interesting suggestions. Some want some form of "sedative" nano which is basically similar to a root. I like the idea but several other classes already have roots/snares/calms. I think a interesting nano would be one that caused the mob to become extremely hostile and attack anything and everything around it (even other mobs). Would make things interesting specially when you encounter large number of mobs in the main room in missions or when your out hunting. You could have ones that affect one target "Temporary Insanity", or area affect ones "Mass Hysteria".
What is your opinion on this? Also what nanos for your class would you like to see?