I don't believe you need to change anything. The sale was fast and furious , i have experienced many and lost out a lot. Its part of the game. Just because a few of the richer community didn't get their dopamine hit shouldn't mean SPL should comprise rarity of the promo card. There were many small buys during the pre sale which i believe is great for the less wealthy community.
If these change were to be implemented i think it would affect the on boarding of new players