Kinect Sports Season 1 was great fun, unfortunately Season 2 doesn't live up to its name.
I think the biggest difference in my opinion is this: In the original Kinect Sports it feels like you are doing everything. For example in Ping Pong it tracks all your movements. You could be standing on one leg while playing and it reflects this on screen. Same goes for playing goalie in soccer and other sports. This was a lot of fun as it felt like I was part of the experience.
In Kinect Sports Season 2 I can't help but feel disconnected from the game. For example in none of the games does my Avatar reflect my real life motions. In Tennis it run on its own (And then doesn't stand like how you stand), in Baseball it doesn't match my stance, golf is the same. The other thing is I can play Kinect Sports Season 2 while sitting on the couch and drinking a bee... I mean Chocolate milk. Maybe this appeals to some people, but I want to feel like I'm part of the experience and not simply a spectator.
Not only does the motion not reflect my real life self disconnect me from the game, but it also impacts the gameplay. For example in golf and baseball I can do a slight movement barely moving and it will hit the ball really hard. (In real life it would move 5 feet.) This didn't happen in the original game. For example in Ping Pong you could hit it hard and the ball would go hard. You could hit it light as well. Everything about Kinect Sports Season 2 just feels dumbed down to the point of being mind numbing. Basically the game requires ZERO skill and while this might be fun on the first play. You quickly realize you've mastered the game by simply popping in the disc.
Score Breakdown:
Graphics: 7.5/10
Sound: 8/10
Gameplay: 4/10
Overall: 5/10 (Not an average.)