I do genealogical research too, but that isn't the purpose of the obituary. The purpose of the obituary is to notify people connected to the deceased that they have died, to whom they may send condolences, and to get information about final disposition of the body (ie funerals, memorial services, etc.)

Death is a very emotional time, and obituaries are very expensive to run nowadays, especially in large urban areas. While the idea to write a considerable obituary is a lovely one, it is probably better off done as an online obituary, or as a keepsake for family members. We made a CD of our family photos for my mom's funeral, and people loved receiving that as a memento.