I don’t think it makes sense to bake in a specific application level system right now. There is an entire zoo of different projects, proof systems, etc. The jury is still out IMO which is better.
As a rule of thumb, a general purpose ZK system would be beaten hard by a specifically designed system. Therefore, I think having an abstraction where the zkparachain specifies it’s circuit/verification key, as Rob proposes, is important.
What I know for sure is that having a wasm interpreter running in a risc0 is a pretty bad idea efficiency wise.