Both FujiFilm Z700EXR and Panasonic FZ200 have 12.0 MP resolution sensors but FujiFilm Z700EXR's sensor is 1/2-inch (6.4 x 4.8 mm ) and Panasonic FZ200's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since FujiFilm Z700EXR'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 Panasonic FZ200.
Below you can see the Z700EXR and FZ200 sensor size comparison.
FujiFilm Z700EXR and Panasonic FZ200 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.