There is a lot of room between "name/relationship" and "all research completed". After two years experience on WikiTree, my method is to add a profile only when I have a name, solid birthdate and relationship.** If all I have is a name and relationship I now generally do not start a profile using estimated birthdates. For example, if I have the name of a child or sibling from an obituary or will, I will indicate the person and relationship in the biography of the profiled person until I have a birthdate. Because WikiTree profiles, including biographies, are fully searchable, others interested in the person should be able to find the relationship if they use all WikiTree tools available.
** Usually a relationship. I have created "stand alone" profiles for my grandmother's foster parents, for example, and indicated the relationship between them and my grandmother by linking them in the biography section.