And
even if further advances in ML can improve the "writing quality",
overall quality is a much more multidimensional thing, and being able to produce a convincing-sounding review (formatted correctly, talks about actual content within the review, etc) is
not the same as giving a
useful one. As another comment in this subthread noted, if the author feels that an LLM-generated review is worthwhile, they can feed it to one themselves—and it's entirely possible that a specially-trained LLM
could give some halfway decent reviews of some basic things like spelling and grammar, missing information or sections, that sort of thing, simply based on previous article drafts and their reviews.
We should not be predicating our concerns about LLM-generated content solely on its "quality", because ultimately, the problem with it is that it is generic. I think it unlikely that it will have the ability to produce a genuine and thoughtful critique of a journal article until and unless there are significant breakthroughs, possibly even to the level of achieving AGI or something like it. Even using a more-advanced review-specific LLM like I describe above more widely does present serious concerns, because it runs the risk of suppressing articles that deviate from the "norm" in ways that the LLM doesn't have any way to appreciate, but which can present the findings better or even make the science better.