Tera: Personaly what we think would be amazing is if there were a summoner class in this game BUT, in order to summon you would have to sing the "song of the elements" that would cause a mini-game thing to pop up to control them. You would have to use this song to control what the elements tried to do.
For example, it could be very similar to DDR(Tera Gold). You could set what each summon was trying to do, and then when your summons tried to do something, you would have to press a button according to what they were trying to do or their damage would be decreased or they would fail. The more summons you had out the harder it would be.
The summons you would call would depend on where you were in the game world. This would be a class that would be completely based on skill and muscle memory. really hard to play, but it would give nice game(Tera online Gold) play.