This concern about breaking only seems true for the Node.js side. The HTML/JS/CSS running in the web view should be pretty resilient to version upgrades; web devs are used to defensive, backward-compatible design that handles multiple browser versions.

The bridge itself is API stable. evaluateJavaScript:completionHandler: isn't going anywhere.

So the question is whether it's okay to use a native web view while still bundling your own V8 + Node. That seems like an improvement to me!