Inca

[Alastriona]

It's not just the Inca, there are a lot of civilizations that end up being powerhouses in Civ that real world history remembers as a footnote at best. Before they nerfed Jaguars Monty was something of an unstoppable beast, and Charlemagne tends to perform much better than you would expect (I think that they gave him a good AI to make up for the odd mashup of traits that he has). Korea is another one, as are the Celts and FREAKIN' SHAKA.

Then there's the opposite, the civilizations that in real history were the movers and shakers but in Civ almost always end up being jokes. Spain built a vast empire in our timeline, but Isabella is almost always the backward religious nutjob in my games. Every time I get a map with Greece it becomes someone's one-city vassal. The United States typically ends up being a small power if it starts at all near a warmonger, and Egypt gets big but then never does anything - except fall over and die if anyone cares to put them out of their misery.

Thats just . Most of the empires in civ were great in their glory days. Just because the zulus got vanquished by the english and their tech superiority doesn't mean they werent a powerhouse on the african continent before that. Same goes for the incas.

 

[MaximumPain]

The Incas seem to fit well with the common human strategy of early wonder whoring and fast tech. Also that UU is one of the best. I don't think it really becomes obsolete until you are facing longbows or crossbows although you do need to use it in a combined arms role once people have ax's and swords men. I found that having a few around in your attack stack is great when the defenders are using archers and its so cheap and quick to build that you can throw them against the walls without to much worry. Not only that but using them extensively like that will get you an early general or two which only makes you stronger. With that financial trait the Inca can recover quickly from breaking their economy by conquering to much. I don't play them much anymore because they do feel broken to me hell even that terrace is one of the most useful unique buildings in the game.

 

[Iranon]

Long-term economy traits? Check.
Most extreme rush in the game? Check.
Easy and reliable barbarian control? Check.
Early, expansion-friendly Unique Building? Check.

It's a powerful civ in its own right, and arguably pushed over the top because the AI doesn't defend adequately against Quechua rushes (they keep using archers when they should rely on warriors).
As an aside, Quechuas don't really become obsolete once you start facing longbows either... if nothing else, they are still dirt-cheap garrison troops and upgrade fodder with a promotion thrown in.

I like them best even if I don't rush... on high levels, barbarian archers can be a pain. Also, Stonehenge may require too many concessions even though Incas can get it more easily than anyone else, which increases the value of the UB.

 

[CornPlanter]

(they keep using archers when they should rely on warriors).

I believe there was a discussion on this and the agreement was, that archers are better than warriors against quechuas. But I might be wrong.