War Wagons are a bad idea for a 80 pop civ

Cortez’s Trebuchet would be better off as a cheat unit, rather than being an actual unit for the Spanish. I am not really sure why you think it would be “cool” to give them a weapon that ended up becoming a failure. If there really needs to be a catapult unit in the game, which will be available for a civilisation, then the Couillard would make more sense which will be an unique unit for the French.

When it comes to unique siege units that could be given to the Spanish civilisation then the Pedrero and the Ordoñez Gun sound like good contenders as suggested by @HoopThrower.

Anyway, back to the topic for this thread I wonder if it would be possible to increase the max population in the game to 300 in a future update. Maybe that can help civilisations who are reliant on military units that takes up many population slots like the Germans and Lakota etcetera.