Ever since the camera was invented, we have used it to preserve images of our families. From wet plates to present-day digital images, we have come to expect family photos to look like this:
One reason is because wet plates, larger format negatives are expensive to develop. The minimum we expect in a family photo is to see everyone's faces and eyes on the camera. Even today, the pricing models adopted by most family photography studios is one that emphasizes the sale of prints or individual digital image. If I am going to pay more for additional images/prints, it makes sense for me to choose those that look like the above.
Unfortunately by doing so, many other fun, crazy and candid images often do not get to see the light of day. Kids are not genetically programmed to sit still and look at the camera. They are free spirits housed in a growing shell of a body, and to jump and laugh and sulk and cry are what make them so special and different from adults. The real gem of a family photo is not to make them look and behave like adults, but to portray them as who they are. Then, adults are free to join them but in a juvenile form.
Rather than printing one large "prim and proper" family portrait to be hung on the wall, try printing several smaller ones of the less formal types. They will not only brighten up the walls, but give them life as well.