We recently talked about a black dial Calatrava in Jerome's post "What new Patek Philippe watch for 2011?": a lot of us were awaiting something like this and the 5153G surely is a superb timepiece. To my eyes, only a detail could be improved : the date aperture. Hoping not to appear unpleasant, I'd like to propose four design options.
1. date aperture without any frame

2. date aperture without any frame, with a cut hour-marker on the right

3. date aperture without any frame, with a cut hour-marker on the right and the same cut hour-marker at 9

4. date aperture with an "arch-section" frame (my favourite).

Ciao!