Honestly, not sure. It would be interesting, but not sure how useful.
The question is who is going to run it and on what boards. For low-end SOHO routers there’s *WRT, for midrange there’s EdgeOS. Readily available multi-NIC embedded boards suitable for running something like VyOS are uncommon to nonexistent.
Personally I think VyOS should focus on virtual environments and x86 servers, as this is where the need for extensible open source system is the most acute, and also where there are still few products available.
If you have a valid use case for it, I’d like to see the result, and accept patches or help with improving compatibility with different hardware platforms if I can (which usually improves code quality in general, unless it’s done entirely in workarounds wrapped in #ifdef’s).