Hear! Hear! I was just going to say Cossack's lasted the longest Samurai, Rider's, and War Elephants, All replace knights, And as soon as you get Cavalry, they are useless. Cossacks however, dont upgrade to anything. (like Cavalry) And The only bonus for war elephants is they require no resources. Samurai get an extra defense, And riders an extra movement.I use cavalry to fight infantry weakened by artillery. The cossack doesn't go obsolete until tanks arrive. Plus, they can be upgraded from knights. It's just a shame the Russians have such bad traits.
Just watch Patton, that should whip you into shapeIve just finished watchin the movie "Saving Private Ryan" and am considering disbanding all my millitary units in my latest game (especially my transporters and marines).....got a guilty concience now lol

All in all, The Japanese, While good, arnt the best all-around civ. Good on an Island? yes Continent, sort of, Pangea (what i usually play) no. Thats their weak spot. In my game.,
And they can sometimes be bad when next to a Mountainous region. But Mountainous region's hamper everything except industrious civs, Who seem to thrive in an closed off-environment.
I suppose everything depends on th staring position, the type of map, and the players stradegy?
On a side note, Egypt is in the lead poll-spot followed closely by Japan and Greece (those Corinthian Hoplites are certainly good... but that good?) When I'm Greece/France everyone takes advantage of me... You NEED those Defensive units!