@Riot Questions on complexity in champion kits

Technically 4 questions:

Who would you say is the most mechanically complex champion right now? What is the ceiling for you when it comes to champion kits? What methods do you use to gauge complexity? Have we already hit that ceiling/Do you feel you can push champion complexity further?

For the last question, I definitely don't mean pushing for complexity just for the sake of it. More like if there were a particular gameplay pattern you were thinking of, and it worked well, would you shy away from it if it seemed like it required more mastery than the next most difficult champion?