I don't think Killzone fits the bill at all. It's really a boring sounding franchise that doesn't capture the imagination of gamers at large. The new one looks pretty but I won't buy a system for it. None of the anounced launch titles really fit that bill.
If Final Fantasy XV has gone PS4 exclusive, that could be the title. I don't think it is though. I think it will be either multiplat or PS3/PS4 cross gen. If it's cross gen it probably won't be a system seller, though there is precident: Twilight Princess was a system-mover and sold a boatload of copies, the vast majority on Wii and not GC. The difference is most people didn't have a GC and the Wii version released first and with motion controls - a major upgrade. If FFXV is on PS3&4, most interested consumers will already have the PS3 and won't bother with the upgrade. This situation is like Wii U's 3rd party launch lineup, with most consumers seeing little reason to buy a system for games they can already get. This will be expecially true if PS4 is expensive.
I think the first big title for PS4 will be whatever Naughty Dog is working on. Assuming it's Uncharted 4, I think that will be PS4 exclusive, and will draw interest.
