I think if you want to become a English Teacher you should go out and do it, follow your dreams. But remember this, things are never what they may seem. Though Japan Looks like a great place to live, Its just like any other place on earth. The sky is blue, the grass is green.
I myself love Japan and I have been there, but no matter where you are is almost always the same. Theres two sides to each coin. But even knowing this I still plan to live there someday. Don't let some assholes steer you away for you dreams.
Though a lot of jobs (for Foreigners) in Japan revolve around Teaching English, you could always become a Translator, but this takes years of hard dedicated work. English Teaching is the easy becasue it is natural to a native speaker. Thus the reason a lot of people (in a big hurry to live in Japan) run to this easy ticket. And theres nothing wrong with that, I know a couple of people who do this and have good life's.
Becoming a Translator can have just as many perks as there are flaws. Though you meet lots new and interesting of people, you can also meet a lot of assholes too. (But then again where isn't assholes these days lol)
Well your the maker of your own destiny. What you want to do with your life is up to you. I plan to make the best of what life gives me
whether it be in Japan or some other place. Right now my sights are set on Japan.