More information leaked online on the upcoming Tokina ATX-i 11-20mm f/2.8 lens:
For comparison, here is the lens design of the current Tokina AT-X 11-20mm f/2.8 PRO DX model:
Here is a report from fotomagazin.de:
The changes obviously only affect the outer, modernized appearance of the frame and the coating of the front lens: According to Tokina, it has a new water-repellent anti-reflective multi-coating, which improves light transmission and minimizes reflections. The coating also makes cleaning the surface easier. The Nikon version of the Tokina has a silent drive focusing motor (SD-M) in combination with a GMR sensor. Apparently the predecessor didn't have that. This explains the changes in dimensions and weights.
Via Nokishita, NikonRumors