I think the 7D Mine Train, from photos and diagrams that I've seen, won't have anywhere near the speed or "thrills" of even the Barnstormer, but I still think it will be innovative and fun. The proof will be in the pudding, of course, but I agree there's no way it would rate as a "E" ticket attraction. If BTMRR and Space Mountain are "E"s, then Barnstormer would be no better than a "C" or maybe C+. Thrills alone don't make an attraction an "E" level attraction I know, so I'm hoping the new technology of the Mine Train will give it a boost as a new type of attraction. How good it will be will depend a lot on what you see from the cars, (scenes and theming) and not just the physical sensations of the cars and track.