John Smith
Smith, John
Smith, jr. John
John Smith, jr.

Arguments:

As with normal nouns, proper names don't need to be surname-first for computerized searching purposes.

ARGUS has a separate "Sort by Name" field, so there's no need for the term to be surname-first for alphabetical sorting.

If you are starting from scratch, there is no need to reinvent the wheel here. Anglo-American Cataloguing Rules, 2nd Edition provides standards used in the library profession for constructing personal names as subject headings. AACR2 deals with issues like honorifics (Sir, Rev), articles and prepositions (Du, Van, De la), pseudonyms, nicknames, royalty, and so on. It also covers corporate/organization names.