Really interesting! We approach it a little differently: in DeFi, there is never a need for users to sign transactions per se (aside from force inclusion of ordering gadgets), they only should send intents that describe how their balances should change. All positions are tokenized, so this doesn't get any less generalized. This way, we can fix all these problems on the smart contract level, rather than the protocol level. Many layers of the above also get MUCH cleaner. And it's more difficult to do things you shouldn't do in smart contracts!