The original 1.x Amiga Workbench was IMHO just ugly even when it was current (I would know, I owned an Amiga); of course it was just the best they could do with the 4 colour palette they allocated to it. The general design was still good. The look of 2.x was fine. I never had a mac, but I think that classic mac is indeed ok and I do like Aqua. For me the prettiest GUI design is still classic NeXT and I would still use WindowMaker on linux if it had more modern WM features.
The biggest issues with these old environments is that today we are used to much higher screen resolutions, but a modern WM with a classic look would be pretty good for me (and of course with themes you can mostly do just that).
The biggest issues with these old environments is that today we are used to much higher screen resolutions, but a modern WM with a classic look would be pretty good for me (and of course with themes you can mostly do just that).