This is a joke.
When the eastern conference championship is being played and Derrick Rose is trying to carry the bulls offence against wade and lebron then this trade is no longer a joke.
Pierce gives them the best chance to win a championship. Rose is the only player on there roster who can create a shot for himself. Pierce instantly takes pressure off of rose to be the man every time down the court. Things can change quick in the nba (ask brandon roy) you never know when 1 injury ends your championship chances and sends you back to the basement. If the bulls feel they want to win now then they pull of this trade.
Being the City of Chicago and having a young MVP superstar the bulls will have no problem bringing in a replacement SF after pierce retires but for the next 2 years paul gives them the best chance to win.
I don't think at this point in Paul's career he gives them a better chance of winning. He's become a three point shooter and has had trouble getting his shot lately. Deng is in the the prime of his career getting to the bucket and free-throw line at will, and hitting shots all over the perimeter.
I think Deng's youth and athleticism gives them a better chance than Paul does right now.