IMO Davis is better than Hickson (long term), and possibly Favors. Favors is very young though. Hickson on the other hand is... I don' know, hes just not good. He played good at Center position in the last 20 games last season, but besides that, he was just not impressive and most of the time - frustrating.
Only Cousins, Monroe and Love are young guys who looks more promising on that list. Other mentioned guys are older players who already founded their niche, while Davis was just a rookie. Sure Davis may not gonna be as good as they, but I dont think people really believes Davis will be the very best player of his position, and after all, it's not comparable, 3-4 years age difference in basketball is huge. Do not compare Taj Gibson to Davis, Taj is already 26!!
Look, try to post ALL MOST PROMISING YOUNG (u23) NBA bigs :
B. Griffin, D. Jordan, D. Favors, D. Cousins, JJ. Hickson, D. Arthur. D. Blair, B. Lopez, J. McGee, G. Monroe, K. Love. A. Randolph, S. Ibaka.
13 young centers and power forwards, not too much. And Davis is better than some. In power forwards rankings, I would say, Davis is ~6th.? Not bad, he is also a lil younger than most players ahead.
Rookies are not included. We need to wait to see them play. But IMO, best NBA rookie bigs are : D. Williams, K. Faried, M. Morris, Valanciunas, Motiejunas, Kanter, Biymbo, T. Thompson. Very doubt in Nikola Vucevic or Jeremy Tyler, Mirotic is not a real PF.