So I ended up renting Killzone 2.
Now why in the blazing fucks would the response timing of the controller to character be so drastically different in Campaign compared to Online? Well, it is. The Campaign plays just as terribly as I expected as I saw in the demo, and the multiplayer plays magnificently.
If whomever made this game is all about adding 'weight' to the character, then why did they remove said weight in muliplayer mode? Wanna know why? Because the weight argument is bullshit, and would destroy any chances of any FPS gamer taking this game seriously. It'd be a chore to actually aim at people with any confidence, which is why I'm sure they made the decision on taking out that horrible gimmick online.
Soooo all in all, Killzone 2's multiplayer is pretty damn good, with no control issues. Just skip the campaign.