tbh, I'd go for a 160 default, but this malicious actor stuff is all just FUD. It's possible today with inscriptions *and* OP_RETURN via libreRelay and a willing miner. Packing crap in the witness data has been possible for the past 4 years. What are they waiting for? "contiguous bytes", which this change makes slightly easier to do? That's the only thing stopping them?!