It seems that the biggest issue of the proposal is the low lvl card limit, some want more some want less. I remember at some point there was reduction of rshares for playing underleveled cards, so we can just bring that back and make a new calculation which can be quite aggressive, e.g.:

In case of a win if you:
play 1 underlvl card: rshares -20%
play 2 underlvl cards: rshares -50%
play 3 or more: you get zero
also if you play only underlvl cards: you get zero

This would allow any cards to be played, but with a penalty. It also removes low lvl accounts playing in higher brackets.