Isn’t that one of the problems of X86? Extension that get used just barely enough that you have to include them, but not enough that they should actually warrant transistors.
Unless you want to make application specific processors that's just a reality. We are gone include things like crypto even if the computer never uses any crypto.
The thing is, for some things you can get 100x improvement. Even if not used often its gone make a difference.
But for them most part, things that are part of RISC-V RVA23 profile make sense to be on a standard PC or Server.
Asked differently what isn't really necessary that is in RISC-V? One could make arguments for a simpler vector extensions for example. And a few other tiny things you can argue about.
Overall RISC-V RVA23 is a reasonable and feature complete set for a modern processor.
x86 on the other-hand has quite a few things that are not really needed if you redesigned it.
