McA123
Prince
I think that this is a pretty big problem, these 2 civs never die, and end up being a major thorn in the side of America and Spanish, French and English Colonialism. I think a brainstorm is in order to try to come up with some sort of way for them to die!
The only real thing I can think of that hasn't already been tried is for, say, conquistadors to spawn in South America at a certain point if Spain is present in the area. It's not a very good idea, but it's all I can come up with.
Also, setting them as MC's was already tried, to no avail, and the problem isn't that Spain, France, England or America won't declare war, it's that they won't invade.
The only real thing I can think of that hasn't already been tried is for, say, conquistadors to spawn in South America at a certain point if Spain is present in the area. It's not a very good idea, but it's all I can come up with.
Also, setting them as MC's was already tried, to no avail, and the problem isn't that Spain, France, England or America won't declare war, it's that they won't invade.