Todd, perhaps it's not readily evident what additional information could be found. I've recently been learning more about that when trying to untangle or confirm relationships. Who lives nearby (such as brothers or a married sister) from a census, or who else lives in the household such as an elderly widowed mother or multiple generations in a household. The Acadian censuses have the amount of land and number of animals, or sometimes that the family was very poor with only a couple of chickens. Many records have the occupation of those being married, or of the parents. Recently on a blended family (second marriage) we saw the older children of the first marriage as godparents or witnesses to the events of the younger children of the second marriage. These are all interesting things that could be added to a biography. Not mandatory, but available if you are aware of where and how to look.
Also contracts of land or business sales, inheritances, lawsuits, etc. could be used to fill in the gaps between the "main events". Even something such as the four children died within months of each other from smallpox (can you imagine the anguish). Or a series of babies who died in infancy. Occasionally there will be a mother who died after childbirth, and now imagine that family growing up without the mother - the father trying to manage, and how quickly he remarries (or who is taking care of the eight children if he doesn't). All of these things bring color to the lives of those profiled. I enjoy the biographies that bring in what life was like in the times - wars, family life, who worked for whom, merchants and trading. I like that WikiTree has this capability compared to the dry tree on Ancestry. I don't think I am an especially good writer, but I do enjoy adding flavor to the lives of those people when I can, even if just a phrase or two more along with the source.