Good-looking family! I think the pose is fine, sometimes you do a tight, formal shot, and other times you have them posed more casually. My problem is with the lighting. It appears that you used the on-camera flash, but what that did was to flatten the light. Please try this again, using the flash off camera, or simply for fill flash, if it is on the camera. So you need the main light coming from a reflector or another light off camera. Try to get the light to "model" their features, with some highlights and shadow (not harsh light, nor deep shadow either).