Since posting this it has seen a lot of upvotes (Thanks!) and support.
Since one of the most commented-on frustration is the inability to edit the close date, I thought I would share my work-around:
Since the last update, you can require fields to be updated when moving a deal from stage to stage (pipeline settings). I now require the Close Date field to be updated in order to move a deal to a new stage.
Even though it’s not the original goal of the request (allow us to update which fields are shown on the Deal summary card in Board view, at least stages and deals are sorted by the (previously useless) Close Date, which informs my Deal Forecast report.