I would really like to see a open source alternative that can interface with all sorts of different hardware to manage my infrastructure with a single pane of glass. Sorta Ubiquti - but leveraging things like the Unifi API & the new REST api on Microtek to get me out of vendor lock in.
I don't think I have ever seen anything along those lines out there.
Im actually happy with my unifi setup - but there are some things (like multiple load balanced WAN ports) that should be easy to do, but instead are impossible.