I am trying to write a referee report on a paper and other than things I know are minutiae I have no comments! Other than not showing anything causal (which the authors readily admit and isn’t really necessary for their question), I have no major criticism of anything they have done. The outlet is probably appropriate. So…do I seriously recommend publish as-is? Have you ever done that? It seems like such a cop out.
What you need to do so that the editor believes you (IMHO on the receiving end of these reports) is to explain in the cover letter why you think it doesn’t need revising. So you say what you told me. It exhaustively documents info, it doesn’t show anything causal but the authors are upfront about that and you don’t think it is necessary for them to show causation given the topic, the outlet is appropriate, etc. The authors should be commended, etc.
It’s not enough to say, “accept with minor revisions” because then I’m all… should I trust you, or are you just lazy? But if you can say why the paper is interesting and important/appropriate and anticipate problems that you don’t think are problems, then your letter is really helpful when I have to compare it to someone who, say, believes the paper should be rejected because it isn’t causal. I had a situation like that once with two extremely enthusiastic reviewers and two who wanted to reject the paper outright and one of the rejects and one of the minor revisions were useless because they didn’t tell me anything useful. If the second accept with minor revisions had told me why to accept, then the decision would have been a lot easier for me. (Or if the other reject had said something other than, “this paper doesn’t cite [my papers]” even though it cited a literature review that contained said papers.)