As a reviewer, my goal is to find critical flaws, not to "improve" the paper. Every paper can be improved in 100 different ways, many of them subjective. The authors have already decided they& #39;re happy with the paper as is. A reviewer is not a co-author or a collaborator.

To clarify: the goal is not to "shoot the paper down" - it& #39;s to accept the paper as is, unless there is a critical problem.

The authors have been working on this paper for years; they& #39;ve probably already thought about any suggestion to "improve" the paper, considered it, and decided against it. It should be their call.