I think some of your underwhelmed feelings may come from the fact that SW8 is going to be a more family-orientated coaster to follow The Smiler. There's unlikely to be anything too intense or "scary". Just something to consider.
As for the secret element, I doubt we'll see anything too "out there", due to the media's continued focus on Alton Towers and their tendancy to report anything they don't understand as unsafe, but I would agree that they will try to market a USP of some kind. The idea of a launch and ideas about it going underground have both been discussed, but it seems far more likely that "groundbreaking" simply refers to the excavated ground in which the ride will sit. The launch idea may have some potential, but the profiling at the top of the hill would have to change from the original plans (which is entirely possible).
Personally, I'd lean towards thinking that there's not going to be any game-changing secret element, but I guess we'll find out in due time.
Burniel | Great at theme park knowledge, not so great at designing signatures.