I don't like this at all, but in all honesty the bangs tag was always doomed to fail.
As someone without any no humans posts favourited, the proportion of my favourites that were tagged with bangs when I tagged it up fully (according to my definition of what should/should not count - more on that later) was in the 85-90% region so I do understand the argument that it was too common to have a tag for.
Not only that, but a sizable proportion of the posts that did come up were situations where the character may have had bangs but that part of the body where they would be were not in the image, whether they be covered by some sort of clothing, or facing away or head out of frame. If anything that -bangs search of well-tagged images was almost better for finding these posts than finding characters that actually have no bangs. Someone looking for bangs would obviously not want to find these, but someone looking for a character without bangs also wouldn't.
And not only that, there's the issue of when exactly does something warrant being tagged with bangs? There have been similar issues with big tags in the past (eg. shirt and breasts) but these were solved by taking the maximalist approach, which in this case would just bloat the tag still further. This wasn't much of an issue with tagging old bangs tag specifically because there were so many clear cut cases to tag up. But eventually it would become an issue. Does Yamakaze (kancolle) have bangs? My instinct (and approach when tagging) would be to say no by default as hair beyond chin-length is not what I think of when I think of bangs, even if it's shorter than the rest and the part of the hair which, if cut, would form them. How about Suzunami (kancolle)? The very top part is obviously tied back but there are the bits around the side. Would that make it count? Or hair that is probably bangs but parted so strongly that it doesn't function as such at all like for kuroshio (kancolle)? Heck, there are even posts of Hatsuharu (kancolle) that have/had her tagged with bangs - I think post #3802128 was a mistag but can't be sure. And that's just KanColle destroyers.
And this issue would also affect a tag for the absence of bangs, except it would do so a lot more obviously (as the edge cases that got tagged wouldn't be hidden among a hundred posts like post #2360964) and a lot sooner.
There should be a tag for finding the presence or absence of bangs that doesn't include combining together dozens of tags that still only cover a few specific cases. It seems utterly absurd that what seems like such a simple and fundamental concept would not have any way of searching for it. But I'm lost for how this would actually work. I honestly think the bangs tag was the best we were going to get (none of the proposed alternatives are remotely close to being actual alternatives), but even that was always going to become problematic one way or another.