I generally agree with everything you're saying here, at least in principal (I actually like CBJ - ha!). My daughters are 9 and 12 now and started riding the mountains, EE, RnR and ToT about two years ago, and that is now where they want to go first when we arrive at WDW. We still enjoy the dark rides and other family attractions, but they love a little thrill, so I think for folks to say that true thrill rides are limited to teenagers and 20-somethings is a little off the mark. I enjoy Pirates more than any other ride at WDW, but that is more out of nostalgia (first ride I can remember riding at age 6) than anything else. Once I get past POTC and Haunted Mansion, I am hitting the mountains hard...and that's only if I can get my young children to wait that long!
Of course, as I said above, I also like CBJ, but my kids are bored silly with it and always have been, so it's a rare occurrence that I can talk them into going into that theater. It definitely takes all kinds of rides because there are all kinds of people/families. One of these days, my kids will be nostalgic for Winnie the Pooh and Peter Pan, and they'll make their own children ride those, but they (like I) will still want something that goes a little faster and puts a little thrill into the day. I feel like the theming in DHS and DAK is wide open to adding a couple of true coasters (Incredibles, Monsters Inc., Star Wars, dinosaurs, etc.), and it would not isolate any families. Frankly, either of those parks can use all the help it can get.