1. England (occupy Paris makes it stronger than Castille)
2. Castille
3. Burgundy (their power equals France, but I think their position is stronger)
4. France
5. Austria
6. The Ottomans
7. Bohemia
8. Poland
9. Aragon
10. Portugal
11. Venice
12. Bavaria
13. Sweden
14. Denmark
15. Hansa
16. Novgorod
17. Naples
18. Teutonic Order
19. Vijayanagar?
20. Holland (yeah, they have great potential, but they can quickly be toast)
21. Muscovy?
...
??. Navarra (it's pretty much a one trick pony unless you get REALLY lucky)
...
N-15 Mongol Khanate (Ming&Manchu)
N-14 Oirat Horde (surrounded by enemies including Ming, lack of forts)
N-13. Granada (still better than most new world pagans, I think)
N-12. Chimu (arguably stronger by 1500 than other 'murricans, yes)
N-11 Aztec (Probably the strongest of the mesoamericans, since they have cores on the two nastiest revolt provinces in the region)
N-10. Zapotec (Mexico gets attacked early by Europeans)
N-9 Maya (similarly awkward position to Creek, only American Tribal Despotism, low tax provinces. There is Aztec Gold around, but... )
N.-8 Oyo (Pagan, not in good position)
N-7 Creek (very awkward position at the coast)
N-6. Ryukyu
N-5 Bar (Burgundy will kill you. Very good sliders though)
N-4 Ethiopia (diplomatically isolated, religious mess)
N-3. Kongo (isolated and weak)
N-2 Epirus (Hello, Naples! Ottomans and Venice don't like you either. Also very poor)
N-1. Arakan
N. Benin (like Arakan, but worse situation if they survive)
Of course, it's all arguable and some nations are hard to compare. For example, I have no idea where to put Ming because of their system. Or the Navarra discussion (which I missed while typing this) - yes, typical Navarra strategy is pretty much foolproof if not for Sicily, but does that make them that easy?