IEEE Spectrum in the early 80's had an article on minimal instruction sets. The author made a salient point that 7 instructions did most of the heavy lifting, another 7 did the most of the rest required. He did highlight that one mistake made with instruction sets was not separating the addressing modes from the instruction itself.

There have also been various projects looking at the micro-instruction based machines and noting that extremely complex instruction sets could be designed so that the actual requirements of a programmer or project be placed in microcode. One example was an instruction to search a tree structure for a required value (as a single machine instruction).

Not that I can do anything about it, my conclusion over nearly 4 decades is that we have failed to take advantage of the increasingly denser silicon to make higher level machines, in particular machines that recognise the difference an instruction and a data element.

We can write very high level software languages but all have to be run on extremely low level hardware. Too much commodity and not enough variability.