They need to remove the Zero...

[Vordeo]

... and make Japan's UU Godzilla, replacing the GDR.

That is all.

I wouldn't even care if it were just a graphic swap with no actual ability changes.

I'll also settle for Voltron, but only if it's the lion one.

 

[Thrax73]

OH NO! THERE GOES TOYKO! GOGO GODZILLA!

Sorry, could not resist. But keep the zero and make the lizard the GDR replacement.

 

[Frosty_AUT]

I'd say the Japanese need to have steam-powered mecha. Not as powerful as the GDR, but available as soon as you discover steam power. Can only be built in the capital though, and only when it has a theatre.

[/Obscure anime reference]

Seriously though, why the Zero? I mean there were TONS of different airplanes in WWII and the Zero wasn't particularly outstanding. They should've made the battleship Yamato Japan's secondary UU.

 

[3of5]

while the Yamato was big and awesome (had it been better protected (Fun fact: the Germans had build a superbattleship too and sent it out virtually unprotected too to be sunk very quick), the Zero had an actual very ddecisive impact in the war. And it was mass produced. The Yamato would have been more a hero-Unit like in Warcraft 3 or Starcraft.
Also the Zero was really feared on the battlefield. If you research airfight outcomes in carrier battles in the pacific you can see loss rates of 90% on the allied side, whole squadrons shot down like birds in a thunderstorm. The Zero was definitely a very fine piece of hardware for WW2 and at least as feared and known as the german tanks and subs.
Japan had air superiority in the pacific war and the zero should reflect that ingame. The US won mainly because they were more flexible (there is no shame involved in changing ones doctrine) had crazy industrial strength and had cracked the japanese military codes, therefore knowing where the Japanese carriers were (and lost almost all of their bombers and fighters to get them sunk despite of the Zero fighter shield).