New champion idea

I we got a very good idea for a champion. I don t know for his name but I ve got a very good idea for his ULT. The champ will use some sort of a 4 element gun. Like for fire element he changes his abilites that you make your enemies fire, for ice the enemies are slowed, for earth element he will stun the target and for wind he will get the speed for each auto attack. That s my champion idea but I don t know will this be too op????????????? And his ultimate has a 30 second cooldown And at level 1 you can choose what element you would use until level 6.