CC isn't the answer to everything.

First, there is not a single form of HARD CC that can 1 shot someone, without building full AP (i.e. squishy). Yes, hard cc plus a combo could. But that's a lot of abilities just for 1 target. Which leads us to my second point. Sure chaining hard cc on a champion makes killing them easy, but all that is wasted if use in a team fight where that one player has 4 others to help them out. So yes, you hard cc'd Yi, but the 4 others just shit on you because you used all your abilities on one target.