Fujifilm X-A7 has a 24.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor . On the other hand, Fujifilm X-T10 has a 16.0MP APS-C (23.6 x 15.6 mm ) sized CMOS X-TRANS II sensor and features EXR Processor II processor.
Fujifilm X-A7's sensor provides 8MP more than Fujifilm X-T10'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 X-A7 and X-T10 sensor size comparison.
Sensor Size and Resolution Comparison image of Fujifilm X-A7 and Fujifilm X-T10 Cameras
Fujifilm X-A7 and Fujifilm X-T10 have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.