I’ve added a small feature to the GoW Database today, a timeline view that displays the history of Gems of War in chronological order, with troop releases, kingdom releases, and patches currently highlighted. It can be found at http://ashtender.com/gems/extras/timeline, or via the nav bar at the top of the page.
A big thank-you to @KAYA43V3R for the source material for a large amount of data I had to backfill. The timeline should update automatically going forward whenever I update my site.
Feedback is appreciated, as always. If you have ideas for things that should be on here but are not (classes and weapons are currently absent, for instance), please let me know.