But I like my Aztecs, even if their UA sucks.I agree with Celevin in general on the germans. The ability is too much of a crapshoot. Either there are lots of camps, and I swarm other civs early, which is effective but isn't particularly fun or satisfying, or there aren't, and I'm playing a dud civ.
Landsknechts also aren't really that fun, since on lower difficulty levels combat is far too easy, and on Immortal and Deity its about unit preservation and getting 4:1 or better kill ratios. A slightly cheaper unit doesn't help much here.
Its not just about strength, its about fun to play.
I find Germans, Ottomans, Aztecs and Americans very dull to play, whereas everyone else their ability influences playstyle in an interesting way. [Egyptians not so much either, since I tend no to go for wonders early game, and I don't like war chariots.]

I've been theorizing on how to balance it, and I come up short. I've got a function that changes for both empire size, and turn number... So hard!