I never fought the Spanish. Someone else killed their faction leader and Spain went from #1 military to nonexistent.

At H/H I have had little trouble with the English as long as I outnumber them 3:1.

Getting the last 10 regions to reach 30 is a real pain. I am at 24 now, trying to wipe out the Tarascans while keeping alliances with the Apaches and Tlaxalans. I have so many troops that I am at about -8000 florins per turn, but as long as I can sack a city every three turns I break even. My opponents and allies, who benefit from extra cash each turn, each have a military about the size of mine. One backstab and I will not survive.

With no cavalry the Mayans are an uninteresting faction.