Chandler might not be the best defensive player in the league but he's right up there, and I'd love to see what 15 guys you have ahead of him.
Lin wouldn't make a difference in this series. He never clicked playing Melo and would have been ate alive by Miami's perimeter defense.
Chandler doesn't have elite rebounding or shot blocking stats so you assume he must be a great one on one defender or among league leaders in steals or something. Nope. Then he must be the anchor of a top 5 or top 10 defense...nope.
Iman Shumpert on his own team is a much higher impact one on one defender and disrupter.
On the Bulls alone Deng, Noah, Asik, Gibson and Brewer are much better one on one defenders. Noah's defensive stats are nearly identical to Chandler's, on the league's best defense. Asik and Gibson outproduce Chandler defensively per minute. Chandler doesn't even rebound at any better rate than Carlos Boozer who is considered a poor defender. Not saying any of those guys should be defensive player of the year, but they all play on a truly elite defense and Deng and Noah are certainly at least as valuable on defense...no defensive player of the year talk for any of them, while Chandler is the overwhelming choice.
Around the league just big (or somewhat big) men...
Howard - much better defender
LeBron - much better defender
Ibaka - comparable overall defensive stats, much better one on one defender.
Bynum - better in all defensive stats
Hibbert - comparable defensive stats
Marc Gasol - comparable stats on a better defense
Tim Duncan - comparable defensive stats
Noah - comparable defensive stats on a better defense
Camby - comparable (still)
Humphries - slightly better defensive stats
Millsap -comparable
Perimeter and wing defenders who coaches worry about disrupting their offense more than Chandler:
Paul
Deng
LeBron
Kobe
Rondo
Tony Allen
Shumpert
Probably 5 of those guys I'd say were clearly better defenders and all the rest have as good an argument. Chandler DPOTY is a media invention, it's the "NYN improved up to average for the first time in 15 years" award.