Unfortunately you're the second case in recent history of a popular question being dragged afield and closed (Why is one +21 question On Hold when a similar question is ok with +53 votes? discussed the other).
An incontrovertible truth of RPG.SE is that we don't do subjective discussion or idea generation. We use Good Subjective, Bad Subjective criteria; a question should ask for working fixes not supposition and answers should Back It Up! with something they've done or seen done (or can cite a source of being done).
Gamers, of course, always think they're brilliant and are sure the idea they just came up off the top of their head with will work just fine for you, despite them not having tried it, or seen it tried, or indeed thought more than 15 minutes about it. We don't want that kind of content on this site - SE is 100x better than "Yahoo! Answers" for a reason. I want to be clear to everyone that this is not under discussion; it's how the site works. Go to a forum to brainstorm. We're not going to rehash that discussion, anyone interested should go read all the other meta posts and SE philosophy about that.
Sometimes this is the question's fault. "Hey give me some ideas!" it'll say. Those are easy to nip in the bud early, the question gets closed by community members out of the gate and refined.
But sometimes, as in this case, it's not really the question's fault. Your original problem statement was fine and I edited it to even more specifically say "Does anyone have a system they have used or seen used that works given these criteria?" That is a completely legitimate question and it's asking for the right thing. Furthermore I personally like this question, and think it's a great topic.
But in some cases, especially popular questions on "squishy" topics like [gm-techniques], we get overwhelmed by answers that just toss out ideas and don't bother to indicate if it's a tested answer and how it turned out for them. In these cases we try to police it by putting post notices, reminding the community how they're supposed to act (downvote and flag subjective answers), etc. Sometimes that works. But in these two cases, it didn't. So then we're left with the Catch-22 choice of trying to "save" the question with mass answer deletes or of closing the question. And since we get approximately the same amount of shrieking from a deleted answer as a closed question, and deleting bad answers doesn't stop more from coming in, we regretfully close them once it's spun out of control.
So your question is "what can you do now?" Unfortunately, I'm not sure there's a way to save the current question. The ship has sailed, the cow has left the barn and it's too late to close the door, whatever tormented analogy you'd prefer applies.
Now, for future questions - while your question was licit, you can always try to make it more "drool-proof" by adding prominent notices, bolding, etc. to make it clear "I don't want to hear your guesses, I want to hear tested solutions." You've probably seen questions on the site that have anticipated trouble of one sort or another and added a stanza to proactively call that out. "Should" that be needed? No, of course not, but unfortunately this is the other option.
(Of course, if you do want to hear guesses, then the close is righteous. I am proceeding on the assumption that you don't.)
Also, in the long term, everyone in the community can help questions like these stay open by acting right. Downvote, vote to delete, flag, don't answer with some junk you made up. If this question had 10 answers but all the ones without any backing were downvoted into the negatives, I'd be all about leaving the question open. Act right, teach others to act right.
We've lost two good questions to this problem lately. There's nothing we mods can do to "fix it" ourselves. We need you, the community, to uphold our content standards. Coach users. Don't put up with poor quality answers or those who advocate for it. You can be why we can have nice things.
