Nature journals pilot payment for ‘editorial assessment’

Paying a fee to publish your paper was bad enough, and only a small fraction of universities and grant schemes agreed to cover the author processing charges. Or is interesting whether they will still be happy to pay the editor assessment fee, which does not guarantee that the paper will be eventually accepted for publication. It is also very interesting to see how well this change is going to affect the inclusion, equality and diversity of authors publishing in these journals.

I would suspect that they will take the money and send more paper out for review, swamping referees (unpaid) with a huge burden

Referees could always refuse that burden, or demand remuneration for their time. It's about time publishers stopped leeching off voluntary labour and taxpayers' money.