While the competition is touting change they believe to be revolutionary 2K Sports appears to be resting comfortably at this early stage. The announcement of Michael Jordan as the cover athlete and inclusion within the game was big but the core gameplay advancements and features remain as unknowns. At E3 2K showed off NBA 2K11 to some media outlets which is how we initially found out about the scrapping of Isomotion. Otherwise the focus was primarily on the visuals.
Kotaku has a good write-up on the time spent with the game which includes redone player models, an adjustment to the broadcast camera, and presentation improvements that will be aided by a TNT producer who has been brought on board. Much of the other talk has to do with animations and player control where 2K11 will hopefully deliver an experience that isn’t quite so canned and predictable. You can check out the full article here.
There has also been some discussion of significant improvements to the online performance which has been the biggest downfall of the series this generation. Apparently up until now 2K Sports has been utilizing an infrastructure created back in the dial-up Dreamcast days. The past few years 2K has stated before release that they were implementing new servers or had done work to make online run better but those promises have not been delivered on so it is reasonable that many will be hesitant to buy into that talk at this stage. At least they have recognized it as an area they needed to focus on though so there is some hope to be had there.