Not going to happen
First, the technical implementation of requiring a reason is a programming task that Stack Exchange is not going to undertake. Some close reasons do require further elaboration but “needs more focus” isn’t one of them: this is a deliberate choice by the site’s owners.
Second, there is a reason: “Update the question so it focuses on one problem only.” By your own admission, this question still asks about two problems. In addition it’s verbose and rambling and takes too long to get to the point - almost everything in Bill’s story is irrelevant. If you compare this with other questions you’ve asked that haven’t been closed and have garnered upvotes rather than downvotes, you should see why it “needs more focus”.
Third, no Stack Exchange site requires explanation for votes (up/down or open/close). Opinions differ on whether that is a good thing but it is a thing.
Fourth, if a user can articulate exactly why a question “needs more focus”, they can probably edit it so it doesn’t. Questions that get this vote while clear to the OP are often opaque to the rest of us.