Sabotage Blizzard's creation of World of Warcraft, destroy it completely, remove all traces of it for sake of a peaceful future.
Ensure complexity and a mature audience for MMOs in general, sabotage all creations similar to World of Warcraft for 10 years.
Would also sabotage all motion control gimmicks, except the Wii, and would get rid of the Microsoft and Sony motional control projects, instilling an interest in PS4 and Xbox (720?) or tech upgrades for existing systems. For a better listing of higher tech games, ensuring a wonderful PC game selection.
The Sony and Microsoft motion projects are putting the industry behind by at least 3 years, putting development to a complete halt, while newer tech such as DirectX 10 & 11 (or even 12) will be virtually unused. Way to go guys.