The early versions of Expose were brilliant. One version which displayed all windows that were open, and another version which displayed windows for the current app. You could trigger it via the Keyboard, Hot Corners, or trackpad or mouse gestures (I’m not sure about the mouse gestures though).
Further, the windows largely maintained their spatial configuration as well as their relative sizes.
This was pretty much perfect and I’ve not seen any other implementation that does this better (Gnome is actually getting there by doing a good job of recreating Expose but adding Workspaces to it).
The problem for Apple was that they need to keep changing prominent visual elements to indicate progress, even if the elements get functionally worse. This led to first losing the spatial configuration and relative sizing. Then it morphed into Mission Control which tried to overload a highly successful Mac OS X feature, Expose, to promote workspaces and then full screen apps. And once Mission Control got long in the tooth it had to change for marketing reasons, so we get Stage Manager.
I suspect if Stage Manager or Mission Control would have come first, Max OS X would likely have evolved towards something like the original Expose instead and everyone would have been happier for it.