The UI doesn't seem geared to power users. E.g. Why is the featured image taking up so much space above the content editing area when it's sized appropriately for the sidebar? Imagine you need to update the text of several posts... Well, now you gotta scroll down half the page to the content area of each one.

And all that padding gets you quite the narrow content area. Not to mention it looks like a very basic TinyMCE. Seems like more of a POC than an actual "spiritual successor".