This seems nice. I'm a fan of outliners.

I like your font and the general feel of the application. It does feel like Workflowy.

It's missing some of the features of https://checkvist.com which is a more fully functional outliner tool then Workflowy. Checkvist is also focused on being 100% keyboard driven.

Also checkout http://www.moo.do/. It's a more innovate approach then the other solutions.

I'd recommend adding some inline help for the keyboard shortcuts.