Gary was an excellent defensive player but maybe only adequate offensively at best (which is generous). Truth be told, there really aren't that many post men who are that good offensively.Gray was a very good college basketball player, on the hand McGhee was not. The guy could not catch a cold or shoot outside of 5 feet and probably averaged more fouls then points.
If you want a lottery ticket comparison Stallings signed a seven foot kid named Luke Kornet ranked around 350 a few years ago. Good basketball players come from all rankings.
Let's hope Peace or Efreteui are not another McGhee and more like Kornet.