Well, to be honest though, a lot of the criticism of Electron stems from the fact that it's more than just a rendering engine.
There are a lot of applications where you'd want to take advantage of a browser view or a renderer or a JS engine, but not the rest of the stack. There are native apps where you might want a well-sandboxed JS engine for extension support, or where you're writing all of your core logic in C/Rust but you want to use HTML/CSS for your interface.
Splitting up those components would be useful in a lot of situations.