Automod is what I was thinking of when I said I thought Reddit has some tools to do this. The problem, like I mentioned above, is one of scale. Automod is not capable of making judgments about post quality; it can't do anything to enforce a "must be something someone said" rule, for example. Nor is it capable of flagging the many, many variants of the same low-effort submission we frequently get (not without a lot of false positives, at least). That's what my blog's curation team does, and what takes the most time. We can manage the blog's former peak submission rate of 25-35 per day, but given the nature of Reddit I expect that number would skyrocket, overwhelming the mod team.

Modmail isn't public, is it? It's only viewable to the sub's mods. If it isn't public, then it is not equivalent to asks.