You are now talking about the written Japanese language, with all the (real) problems with Kanji, an imported writing system. True enough, but that has little to do with the Japanese
language.
If you look at verbs, and ignore the rubbish written in most textbooks about "conjugations" (which for the most part aren't conjugations), you'll find one of the most logical and consistent systems on the planet. There are only two exceptions. How many exceptions are there in English?
EditAdd:
What English does have is a lot of redundancy, which can cover up tons of grammatical mistakes and still deliver the meaning. This makes it an excellent language, in many ways, for international communication. If you try to speak someone else's language, and that person knows just a little bit of English, that person can make a lot of mistakes and the meaning is still clear enough, particularly if you're a little practiced in listening to non-native English. Whereas you may make a small little mistake when trying to speak that person's language, and suddenly the sentence totally changes. Heck, even Italian.. use the wrong verb form and instead of saying what you meant "Ah, I'm stupid" you're saying "Ah, you're stupid". But it's hard to mess up English that way so easily.