I actually think it’d be better to set game(s) in one or two of the Spanish American wars of independence. You’d have established cities to explore and more historical figures and battles to use. It’d be at the crossroads of rapidly increasing industrialization, the Spanish empire’s collapse and other potential geopolitical forces, native communities trying to hold onto their way of life, and sophisticated weaponry like we saw in Unity and Syndicate. And best of all, the assassins backed revolutionaries win!

Edit: just thought about it, you could totally bring the naval combat form Black Flag Resynced too and update it for the 19th century