A big hurdle for me was the fact that leagues would be populated with people who are choosing a lower league than their cards are, so they ave maxed cards.

I'm sure many will do that but I don't see it as a problem because said person would still need the skill to place in the top positions.

Btw, Imo, Diamond and Champion are two completely different things.

Both have the same limitation on what leveled cards we can play thus my reasoning to combine the two.