I understand what you're saying, and I agree to a certain extent, but...
you see, we never really thought about singing in english, I don't really mind singing in another language, but portuguese give us this wider range of expression.
and even though we can speak english quite decently (I think lol), we still don't have enough command of the language, we can't always phrase the verses the way we want, we still have that horrendous brazilian accent (just watch some Ayrton Senna interviews in english, you'll se what I mean lol), though, for singing, the accent wouldn't be so apparent.
but I see this changing, especially in the last decade, people are getting more insterested in bands singing in their native language, even in the metal scene, wich is know for its inflexibility, people are a lot more open to this.
Rammstein proved a couple of decades ago that, if your music is good, people won't mind that, it can even spark an interest in the language.
well, that's a long discussion (an awesome one), it could be an interesting thread.
thanks.