I think this tends to fall into "probably shouldn't have been using Web PKI". I can't immediately think of a reason why you'd need a publicly trusted certificate if you're pinning a specific public key.. at that point who cares who signed it?
I do agree that there are real costs with rotating certificates that ultimately may make it impossible for an organization to complete that work in the revocation window. That is very much an area that needs further automation developed and more importantly, for it to actually be adopted. I believe that's what ACME Renewal Information is attempting to address.
"but in those cases the business users are ok with an outage to remediate a real security issue"
Ideally yes, but that might be the same point you find out the certificate was used in some critical system (let's say Air Traffic Control like a previous CA tried to claim). They still may very well not be okay with the revocation despite the security issue. _Those_ are the people that need to stop using these certificates and there's really no way to weed them out until a revocation actually needs to occur.
"Digicert screwed up their system implementation and made their customers suffer."
And those customers are right to be mad at DigiCert. They probably don't have a legal basis to challenge as the subscriber agreement explicitly permits immediate revocation without prior notice, but they can certainly take their business elsewhere.
"It's also disheartening to see browsers in the CA consortium ignore the CA resolutions as well. Like how everyone voted for 2 year certs and Apple did their own thing anyways. Any punishment for Apple come? So why pick on the others?"
Admittedly I'm not very familiar with the various root programs and the obligations they have with CAs, but it doesn't seem unreasonable that root programs would be free to impose stricter requirements then the BRs.
Though I do find it two-faced for Apple to vote for Ballot 193 only to then impose a stricter requirement. At the very least they should have abstained.