At home I had an 8-bit so played around with CP/M and BBS'ing trying to gather shareware (software was too expensive for a kid of course). My first serious experience of "big systems" were VAX 6000 (1GB RAM in 1991!). I'm reminded that many of the useful concepts of that system, some of which you list.. never made it into Unix. One of the reasons I stuck with Solaris for so long later is because it had a few of them.
My first experience with a multiuser system was also on VAX/VMS. It felt more complete and cohesive (perhaps not the exactly right terms...) than early Unixes. I still experiment with it in emulators.