If you want to take a historical look, I wouldn't focus only on who was picked exactly at #6, but instead look at who was picked in that range, say maybe 6-10, as a few different players could have been drafted at #6 in any year based on the team drafting.
Sure Robert Traylor was drafted at #6 in '98, but let's hope the C's would have drafted Dirk (#9) or Pierce (#10) if they had the #6 pick that year.
Plenty of All-Star caliber players in the 6-10 range:
2012: Andre Drummond, #9
2010: Paul George, #10
2010: Gordon Hayward, #9
2010: Greg Monroe, #7
2009: Demar DeRozan, #9
2009: Steph Curry, #7
2008: Brook Lopez, #10
2007: Joakim Noah, #9
2006: Rudy Gay, #8
2005: Andrew Bynum, #10
2004: Andre Iguadala, #9
2004: Luol Deng, #7
2002: Caron Butler, #10
2002: Amare Stoudemire, #9
2001: Joe Johnson, #10
1999: Shawn Marion, #9
1999: Richard Hamilton, #7
1998: Paul Pierce, #10
1998: Dirk Nowitzki, #9
1997: Tracy McGrady, #9
1995: Damon Stoudamire, #7
1994: Eddie Jones, #10
1993: Vin Baker, #8
