I just purchased the 11-16II, having never used the initial version. Testing on a D4 and D800 to use both in FX mode and DX mode.
This sample appears a touch soft at 2.8, sharpens up well by 3.5. Perhaps I'm just too used to the latest Nikon glass such as the 28 1.8 which is sharper at 1.8 than the Tokina 11-16 II at 2.8.
Will have to test more to decide whether to return or not. The reality might be that the latest cameras reveal issues more quickly than older models, and that this len's design, all points considered, is very good. Was still hoping, however, for more crisp sharpness at 2.8.