Interesting idea, could stimulate people to use Stratum v2 / DATUM without having to run a fork of Bitcoin Core:

> While discussing this here it does occur to me that there is a different line of compromise which might make more sense-- Bitcoin Core conflates relay policy and mining policy. The historical reason for this is that they should match or vaguely bad things happen. But in case where there is a dispute over policy it makes more sense for mining to be the more restrictive of the two, because the negative effects largely come from miners including txn nodes weren't expecting. So maybe it would make sense to change the option to be one that only changed mining policy. At least as mining policy it has a real effect (assuming you're mining!) -- I'm not sure, this is just an off the cuff thought.

Though this also sounds like an implementation headache, and it's still ultimately a placebo. Since this would only be used by tiny miners, the thing they don't like will go in the next block.