In fairness, on the 34mm Simplicity the railroad track is on the inner ring (this is the easy way to tell a 34 from a 37). To your point, however, the center of that dial is guilloche (and that beautiful wavy guilloche, at that) which creates a lot of visual interest.
I agree that the Duality dial seems quite sober for the amazing movement that is behind it! The subtle brushed finish and contrast between the main dial and seconds subdial do help (I'll try to post some better photos later this week), but the overall effect is pretty plain, as you say.
Thanks again for the further articulation.
Best,
Gary