Unfortunately guys like Dirk and Manu already messed up what could have been hands down the most epic HoF class of all time, but oh well.
Interesting question though on 5 HoFers retiring the same summer, so I quickly ran through basketball-reference. Note, these aren't all the same HoF class, but represent the last season they played. Also several players got in as coaches, not players, but I listed them anyway, while others had to wait 20, 30, 40 years before they were enshrined. Anyway here's what I saw:
2003: Jordan, Robinson, Stockton, Sabonis (and years from now we'll probably be able to add Steve Kerr to this year as a coach)
1984: Elvin Hayes, Bob Lanier, Tiny Archibald, David Thompson
1980: Rick Barry, Earl Monroe, Pete Maravich, Walt Frazier, Phil Jackson
1976: Billy Cunningham, Don Nelson, Jerry Sloan, Connie Hawkins, Pat Riley
1974: Oscar Robertson, Jerry West, Dave DeBusschere, Jerry Lucas, Willis Reed
1973: Wilt Chamberlain, Hal Greer, Gus Johnson, Satch Sanders
To me, personally, it looks like '03 and '74 are up there in terms of "wow" factor. No clue how I'd rank them.