I have a big boner for Deng because he's an elite defensive player who shots slightly above average (TS%) for his position with a below average turnover rate. This is easier for him because he's not creating offense like Carmelo, but Deng still is at 17 ppg guy with 20% usage rate, so he's not just a spot shooter. You certainly aren't going run an offense through him, unlike Anthony, but I'm interested in the net effect of having him on the floor regardless of whether he is considered a star or role player. I am not trying to preach defense over offense as I think they are about equal in importance. I am preaching that offense is more than what a lot of people think. You don't have to score to be have value on offense. Noah's offensive rebounding, and Amare's lack therefor, are important contributions to a teams offensive efficiency.
Deng has a below average turnover rate because he doesn't create offense, he either sets up for open shots or uses a pull up jumper when he does have the ball, its pretty hard to turn the ball over much (plus Melo has the same TO rate but hes creating significantly more offense, which is much more impressive). If Deng was much of an offensive player he would have absolutely blown up last year with Rose getting all the attention he was getting from the opposing team. You are VASTLY underrating the ability of Melo's scoring, he averages 10 points more per 36 minutes. That is a huge number. Deng is an average offensive player and a good (not great) defensive player. Melo is a great offensive player and a poor defensive player.Plus, I think that Deng's defense has become overrated because of the elite, near historically good, defensive big men that the Bulls had backing him up. Asik, Noah and Gibson are everything you could ask for as help defenders. And on top of that, SF is by far the least important position to be a good defender at, the list of solid offensive SFs in the league that you need to cover is about a half dozen long (Lebron, Durant, Melo, Pierce, Granger, Gay), the other decent SFs (Deng, Wallace, Prince, etc) don't need much of a defensive stalwart covering them because they lack a well rounded offensive game. The only truly difference making defensive wing in the NBA is Lebron, other than him I would take 15 different defense bigs (based solely on their defense) than any wing. The impact of a great scorer is so much more important on a nightly basis than being a good defender.