They showed like one clip of Halo 3 at E3. Halo didn't need hype at E3, Killzone did. Killzone needs all the hype it can get at this point to keep building and building. If you are smart businessman, you don't release a demo during the release of Halo 3. You want to release it when the media is looking for something to latch onto, not when they are falling over slobbering over Halo smashing an entertainment history record.
Thank God Sony doesn't take advice from the likes of you folk 
Threads of Interest:
The Movie Thread: http://www.vgchartz.com/forum/thread.php?id=6880
The Crow Eating Thread: http://www.vgchartz.com/forum/thread.php?start=0&id=3886
The Betting Thread: http://www.vgchartz.com/forum/thread.php?start=0&id=7104
Custom GIFs Thread: http://www.vgchartz.com/forum/thread.php?id=18963
The Greatest Game Ever Conceived On Any Platform
Tag: "I have tasted Obi-Wan's bitter tears"
