Good point, GT Sport didn't even enter my head but you're right about it getting constant updates.
Can you imagine a persistent online game set in the Killzone universe where players can choose to play as either the Earth Alliance Forces or the militaristic Helghast Forces. They could include competitive large scale battles against the two opposing forces as well as co-op squad based missions against A.I. controlled opposing forces, add in a loot system and some kind of class based upgrade path and I can see something like that being highly addictive. Microtransactions could play a role of some kind but hopefully nothing to abusive.
Of course if a game were to ever come I'd firmly be on the side of the Helghast. I always thought a game set from their perspective would be great since they are originally from Earth but broke away to chart their own destiny away from the Earth Sphere of influence. They aren't evil in the traditional sense.
We definitely need a new Killzone.