Can you please elaborate what you mean by the devs being hard-assed? Are they debating another method to sign messages with a segwit key?
i haven't closely followed the situation but i believe it has something to do with the fact that the way we currently sign messages is lacking some features which is why BIP322 exists. in fact core doesn't have other popular functionality either because of similar reasons (eg. mnemonic backups).
For now, electrum signature cannot be verified in most of the softwares....
any wallet/tool that can sign/verify a transaction can already verify message signatures of all kinds. those that can't verify messages signed from a P2WPKH or P2SH/P2WPKH addresses can't do it because that part of their application is not capable of recognizing the "address type". it has nothing to do with the signature itself since as i said, the signature is the exact same thing with the exact same process and only 1 byte difference (recid).