3) can't run iMovie? You do not know if it's inability to run iMovie is hardware limited at all. You are grasping at rumors and conjecture. It may simply be a case that Apple see no point in releasing iMovie for the iPad simply because it has no camera and therefore can not capture movie footage in which you therefore could edit with iMovie. That is far more a logical reason than many have provided for Apples decision.
Steve Jobs is dreaming about editing videos on the iPad.
Walt: So you made iWork for the iPad. Do you see things that the iPad can't do?
Steve: Well, you can imagine all sorts of things for the iPad. Video editing, content creation...
Walt: Does it require a faster processor?
Steve: Well time has a way of working these things out.