> and technical (there's no first-class feature for askers to contest closure

It's not quite that bad: when the OP edits the question, there is a checkbox to assert that the edit resolves the reason for closure. Checking it off puts the question in a queue for reconsideration.

However, there's the social problem (with possibly a technical solution) that the queue is not as discoverable as it ought to be, and provides no real incentive; the queues generally are useful for curators who work well in a mode of "let's clean up problems of type X with site content today", but not for those (like myself) who work well in a mode of e.g. "let's polish the canonical for problem Y and try to search for and link unrecognized duplicates".

Given the imbalance in attention, I agree that reopening a question should have lesser requirements than closing it. But better yet would be if the questions that don't merit reopening, weren't opened in the first place. Then the emphasis could be on getting them into shape for the initial opening. I think that's a useful frame shift: it's not that the question was rejected; rather, publishing a question basically always requires a collaborative effort.

The Staging Ground was a huge step forward in this direction, but it didn't get nearly the attention or appreciation (or fine-tuning) it deserved.