A lot of these people that have all of these gameplay "issues" would NOT be satisfied with a demo or the game. How am I so confident? Because 2K has a certain style of play that relies heavily on animations. So even though a lot of things will be tweaked and fixed, those animations will still bother people, especially if you are a heavy player of other game because it's so different. So when you hear people talking about "canned animations" and other buzz words, you know they will not be satisfied.
2K will always have two man animations, a little bumping on defense, animations that we lose control for a little. That's the sacrifice we make as gamers to have the most realistic basketball game on the planet. That's the direction 2K has decided to go. And because of its success, there aren't going to be too many changes. Think about it, 2K is selling Madden numbers, why would they appease a bunch of people that like another basketball game that can barely sell a million copies? It's a numbers game. They aren't going to change what the majority of basketball video gamers don't think is broke. So if this heavy animation style that 2K uses presents a bunch of issues for you (like losing control) then a demo is NOT going to appease you. Just stating facts