(1) Accept an stablecoin in the liquidation process so the protocol does not suffer from AIR liquidity shortage.
EXPLANATION: Liquidity shortage happens because there are no incentives to spend Air. If you have Air in your account and you would like to liquidate a position, you won't do it because now your account will be on the list of account that can be liquidated. Additionally, if you are an Air holder, you won't be incentivized to sell your tokens because your account will be ready to be liquidated.
⚠ You might think that with a really overcollateralized position you will be able to interact with the protocol without the previously mentioned problems. You are right but in that case the protocol will need a huge amount of initial collateral to start working properly, and small acount won't be able to participate.