Seems to me that West's 3 year $36M deal with Indy sets the expectations for what Deng should get. I think Batum signed a similar sized (per year) deal sat summer. It would be a discount off what he makes now, but is it enough?
3/36 seems about right for what Deng ought to get. From what I've observed the CBA has left the superstars untouched, put a slight damper on mid-level stars (mostly by shortening contracts), and pushed MLE guys way down the food chain. I'm expecting Deng to get offers for around 3-5 years, for 35-55 million.
I think West is a better player, but he's nearly 5 years older than Deng. If I had to pay $12mil per to keep him, I'd do it.