Both Ricoh WG-6 and Panasonic ZS200 have 20.0 MP resolution sensors but Ricoh WG-6's sensor is (1/2. ) and Panasonic ZS200's sensor is 1″ (13.2 x 8.8 mm ).
Since Panasonic ZS200's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Ricoh WG-6.
Below you can see the WG-6 and ZS200 sensor size comparison.
As seen above, Panasonic ZS200 has a infx Larger sensor area than Ricoh WG-6. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.