Actually I think launching with Killzone is a very good idea. From the trailer and the description it looks different and yet retains some of the identity of previous ones. This will be a good opportunity to relaunch the franchise, especially if the game turns out to be very good.
Exactly. At launch it'll have little competition, and the game has a good chance of being the best looking PS4 game in the launch line-up. Both Resistance and Motorstorm did very well when the PS3 was released, even though their sequels couldn't always replicate their sales numbers. Being a PS4 launch game could give the Killzone franchise a nice boost.