NO. Shadow Fall is best of the serie. I'm sure it will be even more sucessful than Killzone 2.
They break the manicheism of the saga, that's not the time to stop it. And dat free maps DLC...

Actually, there seems to be a bit of a misconception regarding that. When you take a look at the sales of recent Sony franchises across their platforms:

1. Uncharted: 17.91m

2. Gran Turismo: 17.78m

3. God Of War: 13.48m

4. LittleBigPlanet: 11.50m

5. Ratchet & Clank: 10.59m

6. Resistance: 8.98m

7. Motorstorm: 6.76m

8. Killzone: 6.40m

The franchise is actually 8th in terms of overall sales. To give you an idea of it's popularity, Heavy Rain sold more copies than Killzone 3. It's actually not a very big franchise for Sony, but they market it and showcase it like it is. 

My guess is that the games are profitable and Sony is hoping that GG can create a hit with one game in the series that will propel it upwards into a more mainstream FPS audience, leading to much higher sales. I like Killzone, and GG is undeniably talented with hardware, but perhaps there should be a shakeup at the studio and a some different managers should step in to create a different sense of direction. They've been working on the same franchise for 9 years I think. It's too long. Thankfully they do seem to be working on a new IP in a new genre. This will be GG's moment to shine, hopefully they step up or the productivity and worth of the studio may be called into question. 

We also have to wait to see how KZ:SF performs.

Just sell like mad everytime it is released...

Yea it's slowing down........

No the console generation has slowed down. People want something new.

Yes, theyre nothing special, imo. Would rather get some completely new games, for change. We likely will get plenty of small arena shooters even without Killzone.

It will be insteresting to see how Shadow Fall will do on the chart for the future....

Actually, they do. Its all lore that is interconnected, including the games. It gives you motivation, a reason, and making you invested in playing, rather then just going from point A to B because that is what the game tells you to do. Clearly lore takes a backseat in KZ, which tells me Guerilla assumes the players are just shooter bros with little interest in compelling characters and deep storylines.

But hey....if the milk tastes better then your milk, then milk away I say!

no,the games do good enough. I like them okay,but it's not my favorite franchise bye any means.

It's time to move on.

I wish I agreed with you sales, I wish I did.

KZ is actually one franchise I like on PS.

I dont think it's great, it's pretty ordinary, 7/10 type games, but it has great gritty visuals.

Until Shadowfall that is,. This one just doesn't seem like Killzone to me. It seems like it's trying to be Crysis or something now. Too many colors and bright light, and honestly the graphics dont grab me or impress me really. I havent played it mind you just judging videos.

Maybe reboot it. I want to see dark and gritty again.

I doubt the series will die, what else does Sony have for first party FPS? MAG, Resistance, Socom, all those many Sony tries failed out. They've been failing at taking on Halo for a decade, but they cant exactly stop trying given the importance of the FPS genre, and Killzone is all they have left.

Anyway sales will be the more important metric too the series. If it sells well that will matter more than it's poor metacritic, obvously. It may sell well simply because it's one of the few launch exclusives.