Dave,
I think there is a fine line between what is or is not enough detail to warrant a profile.
Something that says, for example: "Lewis Jones married Anna (died 1st May 1680, aged 78) daughter of Simon Stone and Joan his wife" is not enough to create profiles for Joan and Simon - Anna is the only known child; we might assume Simon and Joan were married (date and place unknown), and we can guess that Simon and Joan were probably born sometime between 1557 and 1586 (assuming Anna's age at death was recorded accurately), again place unknown. This is too little fact to make a reliable match.
The same Lewis Jones and Anna Stone might have a child listed "Shubael born about 1651" We have a name "Shubael Jones" and a fairly specific birth date; we can make a reasonable guess he was born near Watertown, Massachusetts where Lewis and Anna settled. We have a family unit (two parents and three named siblings). Taken by itself we still have only a name and an estimated birth - but the total available information about the family (dates, places, names) is probably enough to make or reject a match reliably.
Returning to your initial example - For John Smith all details except name, marriage date, and spouse name are just guesses - by itself I do not think a profile for John Smith is warranted.