I'm willing to bet Horizon won't bomb. It will sell a minimum of 2.5 million.

I think Killzone is a solid game but it just misses that epic feeling of other scifi shooters like Halo and Mass Effect. The Hellgast are kinda interesting, but they just lack the personality to keep shooting them throughout the entire game. So it will need a new enemy that is scarier, better locations because the Nazi inspired buildings we seen in the killzone games just aren't that interesting. It needs bigger, wider levels, add vehicles and jetpacks and you got yourself a game that is guaranteed to sell a couple of millions.

Personally I hope they put Killzone to rest though. Horizon looks like a far more interesting franchise that they should build on. If that game has a dynamic day and night cycle and interesting enemies/ locations, it could very well become one of Sony's biggest franchises. 

Maybe they could link the horizon story together

Give it a storyline people actually care about

It probably will but I don't think it'll be solid enough for people to want another one. Or the sales will come when the game hits the bargain bin.

I've always liked Killzone, but it's never been a game that i purely loved. It's always kinda reminded me of Wolfenstein, when i've been playing it.

Unlike Killzone, which has gotten great reviews and lights the charts on fire, right?

Well, yeah, they got good enough sales for the franchise to have 6 games in the series. Also, Killzone 2 has 90.56% on gamerankings and Killzone 3 a 86.38%. So, yeah, they are well reviewed.