Possible duplicate icon next to name
Sometime I begin working on a person only to find that there is duplicate. Yes, I know there is an icon under tools, but how much better it would be if that icon (in red) were next to a person's name when there is a possible duplicate. If so, I would immediately solve the duplicate before anything else.
Furthermore, I might see the icon in the tree, or in a list of children or siblings, in which case I know there is some clean up work that needs done.