This is what Lust wrote in the rule discussion thread:
Easy ways to fix it- Change the sliders into circles
- Reduce the slider's length and use a repeat where the hitsound should be
- Set the slidertick rate accordingly
- Storyboard the hitsounds
Considering about the differences between circles and sliders, you can't change all of the sliders into circles, because circle is not a HOLD object, and not all of the cases can be dealed with clicks, like drums behind long vocals.
Repeat won't work too when the sound is not in the middle of the slider.
People now use slider tick rate 1 mostly because slider ticks in high density is quite "annoying", if you want to cover everything by slider ticks, lots of them will be unnecessary.
And the last one, using storyboard hitsounds. It looks like a good idea, but the sample will still be played even when you didn't catch the object.
I agree that there are a lot of cases can be easily dealed with simple replacements, but exceptions shouldn't be ignored. They still can be used properly if the mapper know how to.
maybe the new guideline can be written with this line:
Sliderslide, sliderwhistle, and spinnerspin hitsounds should be better in continuous sounds which can be looped by itself.
But this is definitely not a good one, and I can't get a better explanation of this. (and with better grammar, of course)
Whatever, I really hope this can be pushed forward for more different things from mappers' creativity.