To these I would add: lack of a rotate instruction in the base ISA, and unix standard extension groups. This makes symmetric key encryption and most hash functions much slower. The Bitmanip extension has a rotate instruction, but it should have been in the base ISA.

I'd also emphasise the lack of indexed load/store instructions again. It is a disaster for any sort of array indexing where you're addressing >1 array using the same index. I found this in the context of multi-precision arithmetic for crypto, but examples come from all over.

On the author's point about multiply and divide in the same extension: crypto is another good example. Lots of crypto really benefits from multiply, but doesn't need divide.

The most important thing about RISC-V is the idea behind it's openness as a standard and the ecosystem around that standard. The engineering of the ISA itself is not what makes it remarkable, and actually leaves a lot to be desired.