For his "bad" english.. when he's singing in english, it sounds bad, but when he speaks, it sounds good. I think its not much proper to sing in "perfec english". In our country its the same. When someone handle english very good, he's not singing that good too. Because when you're singing in your native language and suddenly in perfect english, it sounds really funny

So I think he wants to sing that way - that not so good way. It sounds better for Japaneses.
What do you think?