Alright, admittedly, I still haven't finished a game. I've only played as Japan. But dude. Is it just me, or does the concept of Bushido (units always fight at full strength regardless of current health) seem far and away the more broken military ability any civ gets? Seriously? My 1 HP unit fights at full strength? It's fantastic. I can't count how many times a lone scout has gone all Donatello on some barbarians and beaten down an entire unit on his own. Though I must say... it IS totally fricking wicked when my little 1 HP Samurai unit stood there and cut down everything that came at him single-handedly. Easily the coolest thing I've seen in Civ's military side.
Yeah... I got around to reading about all the different civilization's special abilities... when I saw Bushido for Japan I was like "ummm... okay, that sounds broken." From your description, it pretty much is.
Yup, Japan's ability is broken beyond belief. It makes a military game a joke.
Some of the others are crazy too. Like Rome's 25% build bonus to anything built in your capitol. Hmm... your capitol generally has the best setup, and will get made first anyway... then every other city you get makes that same stuff nice and fast. Super fast expansion.
The Aztec's culture bonus from killing enemies is great. You shoot up the civics trees easily. They let you play a military AND culture game in one go. :p
Meanwhile, some civs got the shaft. Like England. A movement bonus to all their ships? Really? That's it? As always, unless you're playing on a high sea level island map... that's completely useless. You never need ships except for a quick transport. And even then, units can now walk on water anyway... so who cares?