The surest way to tank Splinterlands asset prices is to mess with the card rental market. It's the tentpole of the Splinterlands card economy. I think the 2 day rental is a negative for the rental market because it discourages casual renting and play. I often rent for one day sometimes when I have the time to play for fun. I'm not gonna do that with a two day rental. Nope.
However, the SPS rewards for battling after the airdrop ends is a big positive. So that change provides hope.
I don't think you have to mess with rentals to require that if you want to get a payout for topping out the leaderboard, you need to carry the required power for the entire season.