We do not want to have to add comments when closing things. (It slows us down.)
We've already had a discussion about adding an additional close reason for "not enough details". This discussion occurred because we have a significant number of questions that MIGHT be ok/on-topic/answerable if the OP just went into more detail. So it was thought that adding a new reason would allow us to provide a more useful explanation. However, I don't feel we reached a consensus, so we've not added a new close reason.
(And honestly, I think "too broad" is close enough to what we need; We don't need "too broad" AND "please add more details".)
NE has a spectacular NE Question Checklist in Meta that OP should be led to when their question is not-quite-good-enoug-but-maybe-with-more-info.
Can we make editable, or can SE one-off-edit for us, the message for the Too Broad close reason? A tweak to:
There are either too many possible answers, or good answers would be too long for this format. Please add details to narrow the answer set or to isolate an issue that can be answered in a few paragraphs. Also see Network Engineering Question Checklist on our Meta site.