OP_RETURN is better, but it is still far from being the best way to handle it.

If new nodes will remove that data from their storages, and will keep only a proof, that a given coin is there, then users will have to provide not only signatures, but also public keys, when they will want to spend their coins. And if data converted into public keys leads to unknown or unspendable private keys, then such things would never be touched. And if less and less nodes will provide such data, then there will be less incentive to push them on-chain in the first place, when accessing historical transaction data will be harder than today, and if the effort of doing that will be shifted from nodes to users.

So, in general, it is the question, if some people want to make enough developers angry, to move dust expiry from theoretical discussion land into practice: https://delvingbitcoin.org/t/dust-expiry-clean-the-utxo-set-from-spam/1707