Note that these are just a person's own opinions, obviously not shared by the architects behind RISC-V.

There are multiple approaches here. There's this tendency for each designer to think their own way is the best.

I get that. I just work quite distantly from chips and find it interesting.

That said, licensing an instruction set seems strange. With very different internal implementations, you'd expect instructions and instruction patterns in a licensed instruction set to have pretty different performance characteristics on different chips leading to a very difficult environment to program in.

Note that this is not in any way a new development.

If you look at the incumbent ISAs, you'll find that most of the time ISA and microarchitecture were intentionally decoupled decades ago.