Ideas for future expansions

So I was thinking of civs and stuff for a new expansion if one is ever made, and I'm having trouble thinking of others. Perhaps they could have one centered around the Romans, or maybe go further back in time to the Egyptians or other bronze age civs, then just pretend they made it to when the imperial age took place, which is really what they did with the Mayans and Aztecs considering there is no way they lasted all the way until gunpowder was used as weapons.. I would like to hear other ideas on this topic because the only other I can think of is maybe the Ottomans but I don't know if that would make any historical sense what so ever because I don't really know when it was founded and am uninterested to look it up.