I get the impression that Austin told someone that he was going to go based on who knows what. This may have been said before he has sat down with the family to discuss things. I can't imagine that he hasn't discussed this with Doc before now, but may not as they've both been busy. I can't see Doc recommending he go pro unless he thinks Austin will fall to the Celtics, although I've been under the impression Doc was about to retire so that may not even be a factor.
He is bound to develop more with another year at Duke as compared to being in the NBA riding the pine. He will get better coaching (K), just as good of facilities but instead of being the least important guy there, he would be the focus at Duke and receive a lot more instruction/attention/playtime. No way 1 year from now he is a better player in the NBA than after another year developing under K, then making the jump.
That said, I find it incredibly unlikely we would be courting Trey Ziegler (6'5" guard) if Austin was telling K he was staying.
Thank you for your time Austin.
I do think Mason has a tougher decision with his draft status being quite a bit lower. I can see him really blooming next year with a healthy Cook getting him the ball and playing alongside a legit center in his bro MP3. Seems like a good situation to come back to.

Duke will be great either way with a senior group of winners majorly focused after an embarrassing exit.
JMHO