What makes you think the "middle" (whatever that term means?) understands firearms laws enough to know this is a concession of good will? I've seen no indications a demographic exists that would find this of any value or even understand what it actually means outside of people doing private sales that want to go the extra mile at ensuring they aren't selling to a prohibited person. Can you expound on this?
I'm probably going a little too far out on trying to explain and defend my own example of legislative strategy - it's only intended as an example - but since I've expanded upon the idea pretty heavily so far, I'll stick to using that example.
Let's look at the most common refrain from the "reasonable" gun control crowd - the demand for background checks. Based on the sorts of people I've interacted with on the subject, a lot of people have absolutely zero idea that NICS even exists, much less how heavy a percentage of firearms sales go through NICS (i.e., most of them). We have no evidence that my proposal would be seeing as a concession of value/goodwill because the way pollsters tend to frame it is either "do you support background checks on gun sales" (which is where we get the "90% of Americans want UBCs" stat from, despite the question not mentioning UBCs), or "do you support
universal background checks?" The distinction I draw from this is that people are really only ever asked whether they support the idea of background checks existing at all, or having them on everything, with the latter being a more polarizing proposal amongst the American public.
So, let's pull this back to my proposal. Say we, without any major political stimulus like a mass shooting, inform our elected officials "here's a background check bill that streamlines the NICS system and will result in more background checks getting done on private sales without any risk of a registry being created from it." If the bill gains steam without any major gutting or rewrites, the Rs will likely sign off on it because it appeals to undecided suburban voters without risking the votes of the more hardline 2A demographic since it can clearly be shown to address their concerns, and the more purple-state Ds may sign off on it because hey, more background checks is always a good thing in their book. Even if they're not universal, it's still sellable as an improvement. We'll assume the bill passes, becomes law, etc. Yay.
Now, what does this do in the grander scheme of things? Well, let's say we hit another crisis and the Manchin-Toomey bill rears its ugly head again. The media is demanding "background checks," amongst other things. Sometimes they're phrased as "universal," other times they aren't. The passing of our hypothetical law now provides us with two strategic benefits:
1. It makes some lower-information voters - the sort who think we have none at all right now - ask "why is this necessary? We just passed a background checks law!" Yes, some low-info voters will still sign up for an Everytown newsletter and say "we got most gun sales now, let's get all of them," but the important thing here is that we're bleeding off their momentum because we already cut it off on our own volition.
2. The Voluntary NICS Law, in this scenario, passed with bipartisan support and was proposed by pro-2A lawmakers. This can help push undecideds into thinking "hey, the gun people are interested in improving things and that last thing they did helped; we should consider their input too and see what their ideas are before we throw our weight behind a major proposal like an AWB." Again, not going to get everyone, but more of the anti-gun momentum gets bled off, there's less Everytown Orange shirts at protests, and public appetite for draconian gun laws made in defiance of what a huge chunk of the country drops a bit.
My point is this: we don't really have to do a whole ton with whatever theoretical proactive legislative measures we propose to get out ahead of the gun grabbers and seize the initiative from them. The whole point is to make it
look like we're really self-motivated about improving things and making careful, calculated moves that make people safer, even if it only improves things a little bit and mostly just makes our lives easier. That's how the opposition is working anyway - nothing they propose makes anyone safer, it just advances their agenda and makes people think they're safer. We can use that same strategy for our own ends as long as we're willing to commit to it and play the game intelligently. Doing so makes it a lot harder for the Everytowns and Moms Demands of the world to claim additional moral high ground in the argument, not to mention it takes a sledgehammer to the current social monopoly they have on being the "gun safety" experts. That title should belong to people who know how guns work, and it's high time we take it back.