status-completed A meta post about this has been created, discussion about this should be directed there: Do we want a custom close reason for the Future Works Policy? Revisited
New custom close reason?
This is a bit more specific than most of your answers, but something I've been thinking about for a while.
Background: we have a long-standing policy to close questions about future works (with clarifications about what that means) as Primarily Opinion-Based. In 2016 we proposed a custom close reason for this, and the consensus was that it shouldn't be a custom off-topic close reason since these questions aren't off-topic only opinion-based. If Categories other than "off-topic" should allow custom close reasons was implemented, we could revisit that decision.
Recently, SE made a lot of changes to the question-closing system, one of which was to replace "off-topic" by "community-specific reason" which essentially does implement the above-linked main meta proposal. Now, creating a custom close reason for Future Works would not imply that such questions are off-topic, only that they're unsuitable for our site for some site-specific reason, which is true.
Maybe we can revisit the discussion about this proposed custom close reason?