The principal suggestion for improvement is to provide a summary of reasons for rejection instead of a boilerplate letter that gives the author guidance on whether the manuscript was unsuitable for reasons of topic (originality, topicality, subject-specificity), quality (research, analysis, writing) and/or other reasons. This need not be lengthy (one paragraph can suffice) but nevertheless is far more useful than a standard rejection letter that tells the author nothing, even on a general level.
