Ricoh WG-6 has a 20.0MP 1/2.3
(6.17 x 4.55 mm ) sized BSI-CMOS sensor . On the other hand, Panasonic S2 has a 14.0MP 1/2.3-inch
(6.08 x 4.56 mm ) sized CCD sensor .
Ricoh WG-6's sensor provides 6MP more than Panasonic S2's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the WG-6 and S2 sensor size comparison.
Ricoh WG-6 and Panasonic S2 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.