I don't know if anyone has posted this yet, I figured they have since this idea is was a Mod. Since the last expansion introduced a use for seas and territories, I figure there is only one way to go.. UP! The mod I'm referring too allows ridges and mountains to basically come into play. I don't know if it's still on the steam workshop but it was a great idea! Now i'm not sure if a whole expansion could be centered around mountains and things but it would add in an essential missing element to the board in my opinion!

It would be interesting as well if they instead either went underground, which could be interesting if the water level was present.  Another interesting addition would be an air level, complete with a species that builds flying cities.    Either way I do hope they continue to expand Endless Legend.