While I have no real preference on how we are matched in league play, I would have to say I agree with @holoz0r. There is no disadvantage to facing someone in the same league as you. If the points spread apart is 1 point or 1000 it doesn't matter as long as the level cards we both are allowed to use are the same.

If you enter a league without the max cards allowed to be used and lose to someone with more powerful cards in that league then that is not a match making issue, its a you better level up your cards issue.