Re: Anything we should steal ? - Definitely
When I arrived at MIT in 1969 the decision to use a high level language to design Multics was still controversial. I went to grad school in a place that ran a Multics system (it was Honeywell by then) and it was still mostly PL/1. The Pascal "compiler" used for classes worked by translating Pascal to PL/1 - I was the first person to get the Jensen/Wirth Zurich compiler to compile itself. (Sets were done assuming a 60 bit word.)
It is hazy now, but I recall that file protection was a lot more flexible than on UNIX, with access control lists implemented a lot more cleanly than anything else I've seen.