1&2 sound worse after this update as described.. I'm not really sure why we are still bothering with this when DNSSEC progress means DANE like setups could solve the original E2E S/MIME issues of payment and domain indicating expectation of what its email senders are required to have for S/MIME.

There are some aspects of (possibly positive) deniability by an individual that probably still remain with DKIM but they kind of remain anyway with domain anchored S/MIME.