Fairer yes, but then the game will become boring quickly. There won't be any additional challenges every season. I have played in a Cup competition where there were bots; at first, it was fun, but it became boring towards the end, including the final. A mixture of levels is what makes the Cup different from the other two competitions, and it provides additional challenges.
I would also like to mention that a user cannot expect his team to be the favourite or be among the favourites for every competition every season. It seems that some users don't want to accept this fact.