P2SH was something that everyone was supposed to be using by now because of the "obvious" security need; you're proposed reason for a soft-fork and associated system-wide risk is significantly more niche.
It won't be niche when the PC platform as a whole is rendered unusable for secure applications by firmware-level, airgap-crossing malware.
*Secure hardware wallets need to be here before that happens.
*"Secure" means custom silicon specifically hardened against side channel attacks and such, not off the shelf embedded systems containing god-knows-what vulnerabilities.