I had trouble using the Nodes/Interfaces page - I think adding some simple progress/status notification would have helped. Here's a couple of examples:
Unlike many (most?) other pages, this one has no "Save" button. I scrolled up & down trying to find it, and finally ended up just hitting reload (risking losing my changes) to realize that this page is being autosaved. I think this would have been obvious if I'd seen some sort of notification - like a if I saw a "saving..." string show up after a change, then change to "saved" - kinda like how google docs does it.
I couldn't figure out how to use the "static" IP configuration for a while. I changed the "Auto assign" to "static" on that page, but found no way to enter an IP address, so I just changed it back to Auto assign. After a while, I figured out that I just wasn't waiting long enough. After 5s, thej text box does show up that lets me enter an IP address. 5s is an eternity to wait for a text box to show up IMO. This is probably just because I'm using a VPN - or maybe my MAAS server is just slow. Either way, I think if something popped up to let me know the page was "busy", I would've waited longer.
This needs to be raised to UX since the page is meant to do inline editing. Everything else in the future will change to inline editing.