alt Hacker News> Giving equal visual weight to each icon is an improvement.
Equal visual weight is another way of saying less differentiated.
> "Shape" hasn't disappeared as a distinct visual cue, as the area within the squircle is made of, well... different shapes.
Shape refers to a boundary outline, not interior patterning. A square with polkadots is still shaped like a square.
> A smaller icon is harder to click, because clicking on a transparent area... doesn't click at all.
That problem is only tangential to what shape they allow your icon to be within an enclosing NxN hitbox. Assume an implied framework where clicking on them isn't broken.
Some differentiation between elements must be sacrificed in order to build shared UX patterns between them. I think we can definitely go too far in either direction.
An example of a nice compromise would be the macOS menu bar. Most status icons are monotone, which allows the ones with meaningful color differentiation to shine through without being drowned in the noise or increasing user fatigue.