The way I see it, if dci wanted to add woodwinds, they would have to add a woodwind judge, and therefore, every corps would need to have a woodwind line. But because not every corps would be open to this change, it could only work by making another class to dci with it's own new set of rules. Though I cannot see any of the upper world class or any world class for that matter moving to said woodwind class because they would totally dominate it and there would probably be rules in place to prevent that. So if a woodwind class was started, it would only house new corps, and maybe a few open class corps.
But this is all a big "if". I don't think it will ever happen simply because a woodwind is not a "bugle". It's possible that a marching band circuit would start up that is associated with dci, but it would lose the best brass players to D&BC, and would probably only be used by people to train for D&BC.
That's my 2 cents.