Te tried out the chieftains, but they were not balanced. We had to spend way too much effort fighting them off. We have ideas about how to fix that, but I have been working on a new game that just came to my head instead of Age of Vikings.
The new game is tentatively called "Extinction Events" (though that is not really that good of a name). It is about building a species of animal, and using it to survive various extinction events. The player that has the largest population by the end of the game is the player that wins.
The species are collections of cards splayed in various directions (splay mechanic is taken from both innovation as well as chibi mob). The game is still not playable, but it was fun to start it out. Here are what the cards look like at the present time:
I will post here if it becomes playable.