Luc Besson is a good heated director, yes. But your review has interested me a lot. I recommend that you see The Professional again, so that you have it more fresh. I saw it recently and I thought like you: that the movie had seen it since I was little. But now that I saw it as a grown-up person, not only do I think it's good, but it's even better ... Personal opinion ;)
Good review, this one from "The Family", I'll see it.