For me, the bigger question around this OP_RETURN debate is getting rid of the datacarriersize option (one proposal gets rid of it now, another deprecates it for getting rid of it in the future).

The Core devs are underestimating just how many people construct their own block templates given the popularity of devices like the BitAxe. Given many such miners are principled and won't mine spam transactions, that option is a very important one to have for their own mempool.