In the end though I just feel like it's extra cognitive load to have to think about two different shortcuts to do what is in many ways the same thing.
Say, I've got two browser windows open and a code editor open. I'm wanting to flip through the browser windows to check on things while I work in the code editor. In reality I'm just wanting to juggle the three windows, but depending on if I'm wanting to go from browser to browser it's a different shortcut than if I'm wanting to go from editor to browser. And there's a good chance I'll then need to swap from editor to browser, then issue a different shortcut to go from that browser to the other. When I could have just hit the same shortcut twice.
I've just never really encountered a situation where I've felt like it added something, but I'm constantly having cases where its more annoying.
The 40-year-deep-history Mac answer to workflows like that with a small working set with frequent cross-app-one-to-other-switching IMO is mouse-based navigation + spatial partially-overlapping windows, but this seems to be an extremely foreign concept to Windows/*nix users that grew up on full-screen-maximize or tiling. So I don't think is particularly likely to be adopted by anyone who doesn't already have it burned into their brains at this point. :) There's a lot of these old Mac bones still baked into the OS (e.g. if you have a folder on your desktop, and double click it, and move it, then close it, it'll open to the location you moved it to next time. And that memory is separate from that for another folder on your desktop. Though some of the follow-on behaviors have changed (opening folders in already-open windows used to behave similarly, opening new windows by default).
The 20-year-history version is my own personal lord and savior: Exposé hot corners.
Spaces and no-mouse navigation are still in many ways comparative afterthoughts to mouse-based/spatial workflows. Though as someone with 30+ year of Mac muscle memories in my head, the switching-windows-vs-switching-app concept and awareness of "where" I am relative to it is pretty embedded.