I don't understand what problem this project solves and whom it solves it for. We can already manage multi-site WordPress installations and usually that's done by site admins, not the average content Joe, so does it really need a super fancy new UI?
And what exactly does it mean when you say "WordPress.com is open source"? Maybe I'm out of the loop but the way I understand it is that wordpress.com is a hosted (commercial) service of wordpress.org.
My experience with WordPress is not that the UI is a problem at all, neither multi site management, which I think is in the scheme of things quite niche. The problem with WordPress I hear other developers complain about is the out dated PHP system architecture.
In WordPress.com, "average content Joe", can manage multiple sites, including self-hosted WordPress.org sites (through JetPack plugin).
Disclosure: I'm one of the authors.
Sorry, it's my pet peeve. Downvote away!
Faster (through SPA techniques) admin UI.
>We can already manage multi-site WordPress installations and usually that's done by site admins, not the average content Joe, so does it really need a super fancy new UI?
Yes, since the current UI leaves a lot to be desired. And why keep it to "site admins" and not make it approachable by the "average content Joe"?
Besides "sites admin" in this context is just a fancy name for a person that needs to manage more than one Wordpress sites from the same UI -- it doesn't mean he's super-technical or that the UI shouldn't be made more approachable, faster and better.
To clarify: this uses the WordPress.com REST API, which has been around for a number of years, not the core REST API being integrated into WordPress (the software). Also, not all of WordPress.com is open source (i.e. you can't just clone down WP.com and run it), just the new interface. :)