I definitely was a big alert slider guy back in the day. It took me a while, but I do think the Flip to Glyph feature helps remove the requirement for this if you’re just switching between two modes e.g. silent and loud, or silent and vibrate.
However, I would welcome its return to quickly switch between silent and loud modes. Even moreso, if it could also pick up further functionality that if you switch to silent for instance, it would also silent other features of your device e.g. keyboard haptics too.