3 steals or 3 blocks unto itself has very little difference in the overall score. It's what a players does over the period of the entire game that makes him a good defender or not.
Let me ask you a question. Who was the better defender in 2005, Bruce Bowen or Gilbert Arenas? Arenas was fourth in the league in steals per game with 2 a game, whereas Bowen only had half that. By the way, Bruce Bowen was on the All-Defensive 1st team.
In 2009, was Tyrus Thomas a good defender because he blocked more shots than Kevin Garnett?