I don't see how that makes sense. Writing an API is less work than writing the devtools (which needs some kind of API anyway internally). So without a universal API, any serious new browser would take more effort to build.
Without a standardized way of writing devtools - assuming the web standard is overall simplified - you can expose a more specialized API without the baggage associated with standards, break it every so often, and make it as easy as possible for developers (potentially even users) to port other devtools to it.
I believe that instead of finding the "universal API", we should embrace the fact that there will be 15+ of them, and therefore simplify the porting process.
aka How to tell that you don't design APIs without telling that you don't design APIs.