Canon 70D has a
20.0MP APS-C (22.5 x 15 mm ) sized CMOS sensor and features Digic 5+ processor. On the other hand, Fujifilm S2 Pro has a
6.0MP APS-C (23 x 15.5 mm ) sized CCD sensor .
Canon 70D's sensor provides 14MP more than Fujifilm S2 Pro'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 70D and S2 Pro sensor size comparison.
Canon 70D and Fujifilm S2 Pro 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.