In the Reopen Review Queue, add functionality for "leave closed" so that it may become "leave closed and change close reason."
One of the things that is not uncommon at all in the reopen review queue is someone changing a question from say... 'unclear' to 'clear, but completely off topic', or one off topic reason to another.
While the OP thinks that they've fixed the problem (I've added the necessary code to reopen it from unclear), they've added 500 lines of code and there's no way anyone is going to reopen that.
So, it's a leave closed review action. And the question remains "closed as unclear" which is really a rather unfortunate thing for the OP who tried to fix it.
Thus the request. In the Reopen Review Queue, have the option for a leave closed vote to change the close reason for the question. If all three leave close votes are in agreement (not a majority - a unanimous vote), change the close vote reason for the question to the new reason.
This will give clear indication for the OP and people who come by later about what needs to be fixed for the question to be reopened. It also allows new users who see the closed questions to better set their expectations about what the content of a question should be.
This is more important in sites where the FGITW is in play or where drive by up votes may make closed questions stay around for an inordinately long time leading to misleading and misunderstood close reasons on questions after they have been edited but still remain closed (but not deleted).