Why is it so difficult for people to adjust to a new mechanic in a game ?
Every game is different, and I found aiming and shooting very difficult in MGS3 initially, but adjusted and enjoyed the game immensely thereafter.
Its more about mindset than lag, I feel.
There might be a actual lag which I do not notice, or maybe My TV doesn't exagerrate it so I don't notice, but for a Single Player experience, I think it is nothing to rant about. Adjust and enjoy, if you can't, there are many other games to play. No Sweat !
Personally, because controls are trival to the mechanics of a game. If they don't work, it can break a game easily, even if it's as good as KillZone2. I haven't played the full retail version yet, so I'm looking forward to finding out, but the demo was a pain to play because of it (the combination of lag, acceleration and dead-spot). I think the reason why most people are disappointed and very vocal about this, is because it would take very little adjustments by Guerrilla to give the options available to make it a better game for those that wish.
Controls like the ones found in R:FOM or CoD have been proven to work very well (despite the constant swearing of PC gamers that keyboard/mouse is the only way to play FPS). Why change it, if it isn't doing the gameplay any favours?