AmigaDOS was cool and could do a fair bit, in its day. Mind you, I didn't really know anything about Unix at the time, so my memories may be coloured by comparing it to MS-DOs and the C64 :)
I'm still kinda in awe of the whole 'screen dragging' idea, where two or more desktops, if you will, could share the same physical screen, even if they were of different resolutions. OK, so I didn't explain that well, but if nothing else at least I know what I'm talking about :-)
But yeah, I agree, it's time has come and gone - it's time to let go, people!
(Having said that, I still have about four Amigas cluttering up my spare room)