The ban on unregistered users being able to upload hasn’t made me sign up, I’ve just been uploading to twibooru instead when I find something that can’t be uploaded to derpibooru, figuring maybe at some point the things I upload there will make it here, a lot of them still haven’t.
As for solutions, bear in mind the ban was meant to thwart the efforts of one deranged person who’d been uploading irl child porn to the boorus, unless derpi’s queue system has finally convinced them to stop (derpibooru having been their primary target) removing the restriction could let them come back. I don’t know how active the mods really are here, every report seems to be addressed with a great amount of lethargy (not a complaint, just an observation) meaning the site could be stuck with literal criminal content on it’s front page for hours before it’s removed.
Staff has jossed this suggestion before, but I would be fine with it if they just implemented the same queue system here. The aforementioned lethargy would likely mean uploads would only be allowed through once or twice a day, but that would still be one to two times more often then they’re currently being let through.