He doesn't always use that pattern (refferring to all of their 8 albums). On many of their older albums you can't really tell what is supposed to be the verse and what is supposed to be the chorus anyway. They change things up so much that very little is repeated on most of their songs (unlike Ghost Reveries).
You may find that the growling grows on you over time, I know it did with me. To me it fits the mood of the music perfectly, although to be honest it's not like I'm sitting there missing it on the songs where there are no growls...
