Looks good but this wouldn't fit into the modern-day front-end developer workflow. I'm talking about companies who use pre-processors like SASS, LESS, Stylus, CoffeeScript, Jade, HAML, etc.

As for live code-editing feature, you can already do a lot of these stuff in Chrome's developer tool.

Note: I'm a Vim user. Which I personally think is still the best text/code editor in the world.