Agree with you on the finish of the Duometre... Good, but it could be better ( the Chrono and the Q.L ), at this horological level.
As for the 2d Time Zone provided on the Sphero, there are two things:
First of all it is another complication. Why not?
I hear that it may sound curious, but why not? I kno< some who will be happy with this complication;
2d observation: Remove the time zone subdial, and the amin dial will loose its balance, geometry, as the Time Zone Subdial does echoo to the small second subdial.
Best, and thanks a lot for your input, my friend
Nicolas