I was never a fan of the skeuomorphic icons (and design in general), personally. I think there's a place for flat design and it isn't all bad, in particular peripheral UI elements, like the top menu bar, dock icons, etc. It is interactive elements that should be the ones to stand out, not everything.

If the homogeny of flat design makes the main interactive elements less salient, then everything designed to look 3D with glossy surfaces and brushed metal outlines does the same, just with noise.

I think there should be a combination of both, which I think is why many find the older interfaces from the 90s and early 2000s much more usable.

That's a long way of saying that I prefer the flat application icons and dock on current macOS. The dock stays in the peripheral and the icons identify the application all while not drawing my attention until I purposefully go to it.

I prefer the older psuedo-photorealistic icon style that macOS used to use because it makes dock icons, sidebar items, etc much easier to quickly distinguish. The icons in modern docks all bearing the same shape and rough set of colors significantly impairs usability.

> I think there's a place for flat design and it isn't all bad, in particular peripheral UI elements, like the top menu bar, dock icons

Funnily enough, these are precisely the elements that are flat in the Windows 9x look. (Windows 9x does not have a "dock" but it does have a quick launch bar and a system tray, and these show flat icons.)