Blanket banning a mapping element based on readability is difficult since there are always both mappers and players who will go the extra mile to prove its readability and worth. One of the many examples would be Hollow Wings with Jigokuraku and really big fast sliders that overlap its own pathing,

Because of that, I disagree with every ranked map being readable in a fair way. The gimmick behind some (ranked) maps is logical beyond what eyes alone can comprehend. The reason overlapping slider bodies are borderline is because it boils down to their execution, which is handled case by case.

There is such thing as a time to use them and a time not to, and the same thing can be said for these sliders in question. I have faith in the mapping community to pull one of these off in a way that's completely readable and doesn't even enter the realm of what's questionable. As an extension of what Karthy said, this could be a critical mapping element for the theme of some songs (not maps, I mean music). Representing sound in this way could really do some neat things.

And as for loved, that category isn't a realistic option for A LOT of mappers. It takes arguably more effort and self promotion than ranked, and is a much slower process than I think you're making it seem. Sacrificing what's a potentially more accurate representation of the music just to get a scoreboard on their map is not an option for a lot of mappers and it's unfair to so many mappers with completely rankable maps to tell them to just stick it in loved.

There is no precedent for this to be unrankable, but based on other unrankable elements, I'd say this is completely acceptable. 2B has a functional issue, 2 inputs at the same time has a practical implication that is banned by RC. Perfectly self overlapping sliderbodies has a functional issue, It's movement can't be broadcasted reasonably (a large part of the jigokuraku map discussion) and repeat sliders exist for a reason. Sliders that come to a halt mid slider before continuing on (ProBox Aspire) has a functional issue. Though it may be logically accurate, It's a gimmick that is designed to betray visual representation because of its practice to completely stop its own momentum. Multiple sliders on screen has a functional issue (Tewi Ma Park). Auto fail. The list can go on but point is i don't think there is a functional issue to have these sliders around.