Doesn't have to be super intense- just something a little more- at least as intense as Space Mountain. Maybe one real good drop (like Everest's: the ones on the current ride are all very short or partial because the back of the train is still going up the chain).
I don't find the current one to be that rough, and if that really was a concern, they have the capability to make it more smooth/less rough than the current one. Everest is a good example. What I do find rough is Space Mountain- even as a healthy 25 year old I get kind of sore after it.
I also feel they could incorporate some new effects/scenarios building upon the whole western/mine/runaway train theme.