Well, Deng >>> Carter, who almost certainly is going to come down with an "injury" in the next few weeks and take the rest of the season off.
Assuming he stays healthy he's better than Deng for my team, actually. He hits more three's and has potential to pull down some rebounds for me with the Sun's small lineup.
When Noah returns Deng is going to get less touches which doesn't necessarily mean a dip in production, but I have more faith in VC who is clearly a top scoring option.
Also if you looked at my roster for tomorrow I had Deng on the bench. I couldn't fit him anywhere in my lineup because he was only SF eligible and I had Granger and Rashard in the two F places. As I learned earlier this week players on my bench don't add to my total for the week. Any time I had a full roster of guys playing I'd have to sit one of my better players with Deng on my team.
Now I can simply bench that piece of shit Dunleavy and use Carter instead. I win this trade, easy.