The rhyme always knows better than you, and leads you to places where you wouldn't otherwise have gotten to and that is absolutely the case. Leading off from formal poetry, there is something about when you pay attention to form and you allow it to have its own laws and you listen to those laws you really do end up in places you wouldn't otherwise go. Which isn't to say that I believe in following the rules when I write. I don't. Each of the forms in my books feels to me new.