The idea of Wasm as a universal plugin system is very promising. But string passing is maybe not the best example to highlight, considering that Wasm is introducing stringref to enable zero-copy string sharing between the Wasm runtime and host language.
https://github.com/WebAssembly/stringref/blob/main/proposals...
While it'd be a nice addition, I wouldn't expect it any time soon.
It's currently still a stage 1 proposal, while we've been waiting for years for other proposals to be merged. The last time a proposal was actually finished was over 2 years ago.
https://github.com/WebAssembly/proposals
https://github.com/WebAssembly/proposals/blob/main/finished-...