Why do you think is the vertical tower on Dodonpa, awfully designed, compared to that of Hypersonic XLC which looks smoothed out? People seem to say that's kind of rough.
Just off the top I would venture a guess that it's because of where the top hat (Hypersonic XLC, first commercial non inverting top hat?) occurs on the circuit. On Nega Sonic teenage launch coaster, the top hat is right after the launch, giving the most control over variables in forces and such, with Dodonpa, the hill is much later in the course, which means the margin of forces it has to safely compensate for needs to be larger and therefore, the hill is broader, and less vertical.