Let me explain my view by analogy.
The Bulls drafted Elton Brand. He was co-rookie of the year. He made noises about leaving if the Bulls didn't put together a winner. The Bulls did have Artest and Brad Miller to go with him. And they would have been pretty awesome if the three stayed together. Did Artest make the all-star game? If so, that's three all-stars.
Anyhow, Jerry Krause traded Brand for the #2 pick in the draft and selected Tyson Chandler. All the potential in the world, and he was seen before the draft taking and making shots beyond the 3pt line and everything. P-P-P-P-POTENTIAL!
The moral of the story is, the 20/10 PF bird in the hand is worth 2 in the bush.
And Deng is the 18/7 SF who has received as many all-nba defensive team votes as Batum, and Batum is the P-P-P-P-POTENTIAL guy.
But in the world of CBA economics, if having a SF on his rookie deal is part of the strategy, then Batum is a good one. If it's Paul Allen's money, I'd rather have Deng.