I think this is good, and may also improve reviews. I doubt that Nature has an issue with substandard reviews, but I have definitely seen it in some of the computer science conferences I submit to and have served on [1]. If reviewers know that their review may be published, I think they may turn in more substantial reviews.
[1] In computer science, conference publications are peer-reviewed and highly competitive. We also have journals, but most novel work appears in conferences. The more theory oriented parts of computer science will tend to publish in journals more, but they still publish in conferences, too.
[1] In computer science, conference publications are peer-reviewed and highly competitive. We also have journals, but most novel work appears in conferences. The more theory oriented parts of computer science will tend to publish in journals more, but they still publish in conferences, too.