The VAX was, I think, co-designed alongside VMS. The two together were an innovative design, distinguishing architecture from implementation, a comprehensive isa, a roadmap for the future, etc etc. VAXcluster was amazing integration of both.

I believe the design was influenced by Djikstra's Structured Programming book but have no evidence.

My epiphany on the issues with the isa came when I discovered that the checksum calculation used by the VMS backup utility was faster when done in a short instruction loop over the microcoded instruction. MicroVAX II. Microcodes were a huge barrier between the speed potential of the electronics and the actual visible isa. Duh!

Cray knew this, but he didn't build product lines, just single point products. Sun built product lines with RISC and ate Digital Equipment's lunch.