By the way, Monaco is 10MB+.

That's quite impressive nowadays for something so feature filled, but you're staying for 10MB when doing quick edits.

Monaco is a mature, powerful and pluggable, which makes it a good platform to build on top of. More cynically, it's a good bang-for-the-buck project if you are seeking a promotion. The alternative is building your own. Maybe that doesn't make good business sense. And that's exactly why I'm crafting a good enough web-based code editor under 14KB ( a single TCP roundtrip ). I was optimistic for Cloud9. It was built from the ground up, for the web, and was at a suite spot between being light but entirely suitable inline code edits.