I have faced the editing depth issue in reading other writers’ works-in-progress, both as a paid bookdoctor and as a pro bono friendship read. Being a fiction writer myself I am extremely loath to criticize a work in any way that may seem gratuitous and cruel. I always try to balance out the positive as the foreground comments, or let’s say, the first round of comments; then I bring up gently what I do see as issues one cannot ignore, e.g., a major structural flaw in the plot. But even there I try to be a very gentle critic and try not “to solve” the issue at hand.
The more advanced a writer the more subtle and abbreviated are my comments. For a beginning novelist I find one has to be a bit more detailed and direct. I always add the comment that art is a very subjective matter and it’s finally up to the individual artist to find her voice and vision.
It pains me to have to correct seriously committed writers and so I’m very cautious; but if there’s something that appears to be a serious, aesthetic “blind spot”…(see the Longinus principal). I do feel it’s my job to confront it gently. If the writer wants to expand that into a fuller discussion, ah, then I’m glad to follow that out, again letting them lead through open ended questions.
Also, I try to emphasize the “negative capability” approach, where we step back and look at literary choices from all kinds of perspectives before rushing to a final judgment. The commentaries depend on the writer I’m dealing with. Everyone is different but I’ve found most are quite sensitive in a hidden, deep way. Go gentle into that editing night.