Using a very strict definition, a complication is a mechanism which is added to the base timekeeping mechanism, but has nothing to with it or its performance per se. In this sense, the constant force mechanism of the Zenith Academy George Favre Jacot is not a complication, at least not a real one...
Thus, I consider the Zenith as a highly sophisticated precision timekeeper with an extremely refined and highly developed movement. It represents one of the finest specimens of what should (but certainly no longer is) be watchmaking's core competence. The sophistication is carryed over to the winding mechanism and its haptic feel (thanks to the fusée and chaine). Winding it is believing!
The Zenith is a prime example for the fact that a movement without complication can indeed be very elaborate and complicated to make. A complicated watch on the flip side could easily be mass produced...
The Lange Zeitwerk however is a true complication as the mechanism of the digital time indication does not add anything to timekeeping performance (to the contrary, if at all). It is a chariming, entertaining and highly recognisable timepiece.
In my view both timepieces complement each other very well.
Difficult to come to a conclusion...
Hope this helps!
Magnus