I haven't been able to play through a full game yet due to crashes etc, but I was thinking that it is likely that you can have many cities in a full game, and so keeping an eye on what has been/is being produced could become difficult.  Another game I have enjoyed is called Advanced Tactics (Matrix Games).  It is a tactical war game with no real city management issues, but cities do produce different types of units, and they have what I consider a useful summary page to keep an eye on production, and I thought something similar would be useful in Elemental, as well.  Here's a screen shot of that game's summary production page. 

I also like this page, which shows you at a glance details on all your stacks of units scattered around the map, with a quick way to go to whichever unit you want to.

I think Elemental would benefit from similar pages (under the Kingdom Reports section, and/or on a hot key from within the game) to help manage cities and units in the game, particulary on larger maps.