Shed - I've spent much (dull) time at Hahn's coach station or in the Lucky Luke bar in Latzenhausen killing time between a coach having arrived and catching a plane out. The point I'm trying to make, is that while places like Trier, Koblenz, the Rhine, Mainz, Heidelberg, Worms, Speyer, etc... can be reached by coach from Hahn, they all seem to involve a s*ddin' long time on the coach, or a coach that goes infrequently, necessitating much time wasting at Hahn.
Stansted may not be next door to London, but it's not exactly far away from some things of interest. Hahn by contrast needs at least 30 mins (and more like an hour or more) on the bus to get anywhere of cultural interest !