Pavel,

I agree. I only wanted to make clear, that the impact would be
significant. Lot of parties would be involved with nonequivalent
starting positions.

I agree with you. I believe nonequivalent starting positions are the norm in mining, not the exception and hence don't believe this to be a problem.

I think the ASICBoost can and should be prevented completely.

It certainly can be and from the responses I'm getting, I believe there would be at least a few people that would enthusiastically support a BIP to do that. That is, however, a separate issue than my proposal. My proposal aims to bring ASICBoost out into the open *while it is still possible*. A BIP to prevent ASICBoost completely is in that sense compatible.