I can agree with this. Thunderation had backwards cars for several years (and SDC is a better analogue for HW than Six Flags is), and they were quite popular. I don't think I personally would want to ride Legend backwards though. I took my first ride on it in the dark, and the dark there is so dark I couldn't see a thing. I didn't like it at all. It wasn't until I went back the next morning when I could see where I was going that I liked the coaster. With significant changes to the layout, backwards could be fun. But not on the current layout.
Oh didn't know SDC ever ran Thunderation backwards... I agree they are a much better analogue than Six Flags!
Legend backwards? That sounds fun but painful.