Um - swinging coasters have existed for *decades* and are perfectly safe not to mention pretty darn popular. In fact that was just recently an uproar when Busch Gardens Williamsburg closed down their own classic Big Bad Wolf coaster to make way for future expansion. In all past instances, the swinging coasters have been suspended, hanging from an overhead track. Although the track is below in the Dwarfs Mine case, it's exactly the same idea in that sense.
Um, Matterhorn Bobsleds? You know? Disney's very first roller coaster? The one that is still uber-popular today? The worst impression people can have is that Fantasyland is for little kids. Every land of the park is intended to have features that appeal to every age group. Seven Dwarfs is long over due.