About Killzone having the advantage because PS4 will sell more than Xbox One...
According to VGChartz the only exclusives on PS2 that beat Halo:CE saleswise is Gran Turismo 3/4 and FF X, despite the original Xbox selling WAY less than the PS2.
And about the preorders...
Titanfall doesn't have a release date, it will release next year. We can't see Destiny or Halo either in the preorder-chartz but we all know that these two games will sell bigtime. And I can't remember, when did K:SF enter the top 40? I think Titanfall will have more preorders 12 weeks to launch.