Note the OP_RETURN change by the development team is only a change in default relay policy.
Miners are, as always, expected to make their own policy decisions, and never rely on merely the default Bitcoin Core mining code.
Hopefully as mining returns to being decentralised, we will see less toleration of abusive/spam transactions whether the OP_RETURN variant or otherwise.
Now, if someone has a valid, necessary use case for actually storing hashes with transactions, obviously that's a case miners should seriously consider mining.