I've requested this before.
The Shift-C/Find Next Idle Settlement button at the bottom of the screen really should tab to settlements with EITHER the Build or Train cue open, not just completely idle cities.
Actually, I wouldn't mind if the button cued through ALL of your cities (perhaps Alt-C could do this), so you can quickly tab through your cities and see what they are building/training/outputting, how many units are in said cities, and also if any potentially hostile creatures or units are nearby, without having to open up a menu first.
Scrolling all over the map or clicking on the mini-map until I can find my cities, then having to click on said city in the right place (i.e. where there is NOT a caravan or other special feature) really slows down the gameplay experience.
Yes, there is a 'city list' menu for this, but that button at the bottom is one mouse click away, without any keyboard shortcut jujitsu. There are a few of us that don't often use keyboard shortcuts, you know...
Anything that can shorten time and effort using the interface is a good thing in my book!
BTW, the new build looks interesting so far (1.09o beta), other than the level 3 city crash issue (which I'm sure you'll figure out shortly). Great work guys!