Avatar Movement Program:
Your Microsoft Avatar should be able to move in hundreds of thousands movements, these movements should be unlocked/learned as your overall gamer score increases. Say for instance when you unlock 15g in a game like "Halo 5" your avatar would learn a movement such as a cartwheel.
Upon gaining all the achievements in a game like "Halo 5" your avatar could learn a game specific movement, i.e. an Halo inspired movement such as master chief gunning with the Battle Rifle.
By having Avatar movement rewards program with game specific achievements it would show your friends and your community that you have achieved 100% success in achieving all the achievements in a game that you and friends play. Giving a more visual representation and an increased reflection of your gaming score.
Players will want to purchase games just to increase their gamerscore, in order for their avatar to have more movement options/abilities. If players would like to purchase specific movements they can still purchase them via XBL marketplace. But in this case the Avatar movements that are learned/unlocked from completing all achievements in a single game, should only be obtainable by getting 1000/1000 points for that game.
With the purchase of each kinect game, players are allowed to create a 15-30 second custom Avatar movements. This will increase sales of the upcoming kinect titles and make a significant use of the kinect with the Avatar program. Also these custom movements can be shared via XBL Marketplace.