I had the same problem with COD4, I though that it was just me but glad to hear that its not, I also broke another PS3 controller while playing Resistance 2, the L2 spring snapped and then it just flopped around. (Run, Crouch, Run, Crouch, etc...)
The servers will probably be just fine, thats what the closed Beta was for right? Well if not You still have the single player.
Let's not forget that Killzone came out between two awesome games. First came Street Fighter 4, then Killzone, and lastly RE 5. SF and RE has a much bigger userbase, so what that means is that ppl that were on the edge of buying KZ, but they also like SF they will probably buy SF over KZ, cause they KNOW they will like SF.
It comes down to bad timeing, and little or no advertising.