They myth that 2K is just a roster and animations update is not correct. 14-15 had the least amount of change but since the change in 12 up until 14 they were tampering with the game play.

They usually find some way to fine tune the game play. It seems like they listen to somebody, if not the fans. I will say that 15 was imo the weakest of the bunch so I'm a little worried they may be resting on their laurels, but we'll see.