One of the top things to do about MEV is to make all transactions in a block simultaneous, so for example if you have a price oracle it can be limited to only reporting one price per block so although it can be manipulated to either report a high or low price it can't simultaneously do both. In Bitcoin ordering is strictly enforced but there's a loophole that things which happen in the same transaction do happen simultaneously, so future extensions could be made to only sign things they care about and are okay with transactions getting aggregated just by smushing them together. That of course requires a new signature opcode, because current signatures always sign the whole transaction.