I think we definitely need some sort of system to filter the relatively frequent bad advice that pops up through the Help and Feedback categories, specifically Scripting Support. This is especially true with the influx of New Members–while Members are obviously still capable of giving bad advice, from what I have seen, it is usually New Members who pointlessly post advice regarding things they aren’t personally informed about, or otherwise contribute nothing meaningful to the thread.
I say that as a New Member myself. Considering the weakening of the forum restrictions, (which I wouldn’t be here without), there has to be some way to hold people accountable to their advice. That should be the primary goal, not creating an outlet to discourage people from posting. A Stack Overflow-like reputation system seems like it would work best.
Obviously, this would not be limited to New Members, but the influx of new forum members only strengthens the case for a reputation system.
Outside of the “advice-based” categories, however, I don’t feel like a downvote-like system would contribute anything meaningful. We already have the flag system, which is generally okay at getting rid of meaningless responses or clutter.
I think it might also pay to look at how overzealous users of the flag system can occasionally be. I come across a lot of flags that come off as unreasonable, and representative of a toxic culture, usually within discussion-based topics in which flags are distributed freely for the most benign of violations. A ‘downvote-like’ system should not emulate this; it should be a way for more experienced users with ‘reputation’ to draw attention to poor advice or misleading information. It should also be constructive–require people who ‘downvote’ a reply to post a visible reason, as Stack Overflow seems to do. That way, you can see what’s wrong with a solution, and judge advice on its merits.
I think Scripting Helpers already does something like this. This might be a lot of work to implement properly, but as the DevForum and the help sections grow, misinformation is inevitability going to become more rampant. The Devforum is an extremely useful resource, and this should not be compromised by a lack of accountability–outside the flag system, which requires extra moderation manpower, and can often be too extreme for an (often subjectively) poor response to a question.