You know you're on a non-starter here. More creative means more difficult and the average unhinged whacko as opposed to a dedicated terrorist is not going to go there. A dedicated terrorist will always find some way of trying to reach his goal.
Removing the available equipment for certain types of attacks after the event means another event of that type is less possible. I'm not sure you'd argue that nothing be done would you?
I agree with you on another point that most knee-jerk reactions often don't have the desired effect but...there's plenty of evidence from around the world that some sensible regulation probably will.
And the worst mass murders in history have still been committed without guns. The capable ones will find a way to kill no matter what we ban and the doofuses won't even become a statistical blip. You're for disarming the citizenry (which is harmful to the society in the long run) in order to combat what is realistically a non-threat. You'll save more lives by outlawing peanuts.