Apart from minimum card levels being terrible, I would also suggest less brackets. The playerbase is not that big to begin with and splitting it up in 6 brackets feels overkill. Maybe that is the reason for the minimum card levels? To force people in brackets because otherwise everyone will play in champion anyway, not for the rewards, but for the match liquidity?

Anyway, I would suggest 2 brackets are enough for starters, it can always be refined later. Let's say Silver and Champion.