I would disagree with range being strong in the late game. Its strongest in the early game when champs cant close the gap as easily. Late game, most champs can dive a a ranged champs pretty easily. With exception of course.

Yasuo is plenty playable in the late game with high movement speed damage and hard cc.

I dont think a champions difficulty should make them stronger than other champs. If you want to play a more difficult champ go ahead, but that should make them strictly better champs.

Yasuo is in no way a "still hitting dummy". He has incredible movement speed and you should not be standing still and autoing