On the cup point, I really enjoy the challenge of playing higher level teams who have players at world class and scout level, so satisfying if you beat them! League is too easy, I will win no problem
If I was Level 16 and it was the other way around i.e all league teams better than me, but cup and CL bit easier that might get tedious. They need to be able to put teams of same level together or freeze the level of a team if they are in a league with lower levels