I think that another issue with VLIW as a general purpose ISA is that for it to be worthwhile the compiler has to have deep understanding of the underlying impl

I think that another issue with VLIW as a general purpose ISA is that for it to be worthwhile the compiler has to have deep understanding of the underlying implementation (deep enough to always generate hazard-free code) such that the CPU does not have to contain any scheduling logic. This is the case for most embedded/DSP VLIW architectures. The issue with that is that there cannot reasonably be any kind of backward compatibility on the machine code level.