There's basically no Japanese text in the game except for dialogue. Pretty much all of the menus/screens are in English. Even the wacky Zentraedi unit names are romanized! It's pretty easy to play; just make sure and run through the tutorial.
SPOLIERS.......
It seems like we're running out of characters... Assuming Kuruuze dies and Isaac defects, most of the named characters will be in the "neutral faction" and/or dead!
FM3 was great! I loved the mech customization features! It would be cool if in FM4 you could play through an alternate campaign like you could in FM3....