I had a great discussion with a student of mine last week about keeping photos simple but complete. If we shoot for our family, they will always appreciate those wide, sweeping photos that include everyone.
If you shoot for a readership that does not know your subjects, then another principle applies.
This principle is — always keep it simple, but tell the story — or as I like to say "crop until it hurts."
The oldest photographer trick in the book is if you keep the photo simple, more people who do not know the subject will relate to the image. If it is a child, they may see their own child doing the same thing that is illustrated in the image.
A common fact is we relate to a single individual, or maybe a couple, more than a large group. Instead of a group of children, make it one or two. If you go for more, the children have to be dressed alike or have to be doing something that is very easy to understand or "read" by the viewer.