Samsara, while you're right that Portnoy didn't actually write riffs, he did play a big role in arrangement and overall ideas about the direction of the music. So I don't think we can discount the role he played as a kind of director. It's definitely more than just writing drum parts.
The bolded part. And, he actually DID write riffs and chord progressions regularly.
If he did, cite your source, because in everything I ever read (Lifting Shadows, articles, etc.), and watched (countless interviews), that is not how his involvement has been described.
Don't just "riff" off the top of your head, bosk1. If you are going to be definitive (what I have stated has been on the DVDs and in the book), then cite it, otherwise, don't just guess. I've seen and read the same stuff as you, and nowhere in any of that does it say he writes riffs and chord progressions.
If you are talking to someone who is telling you that, then you need to have them give you the source. Otherwise, that is just BS.
And IF (and that is a VERY big IF) I am wrong, I'll happily admit it and reconsider the situation before posting again. But you need to provide proof. As I said, everything I described in regard to how DT writes songs, was gotten from Lifting SHadows, various articles, and various DVD and interview footage. YOu and I watch and read the same stuff, so I want to know where you got your info.
Name some songs too where Portnoy had the riff and chord progression too. Because according to everything that is out there in the public eye, he didn't write riffs and chord progressions.