(New Videos and Pics) 4.4.1 Camera Blur Experiment
Disclaimer: because a related thread was received with much criticism, I made a new and slightly more thorough experiment. Also unlike before, this one isn't a comparison against iOS, it's just a straight demo of the camera on 4.4.1 on the N5. Of course it's neither flawless nor impeccably scientific, but I think it's clear by now that this can be consistently reproduced.
In this experiment I took 6 pictures in regular lighting, and 6 pictures in bright lighting — per popular request, I'm linking all pictures. The idea was to let the camera focus, then tap the shutter and at the same time begin to move my hand.
My findings: The degree of blur seems linked to how well lit a scene is. The problem of blurred shots with non-still subjects is significantly diminished thanks to the 4.4.1 fix, but it's still a problem. Finally, this test doesn't demonstrate how much worse the blur problem is in real-life situations (for me, that means shots of baby relatives), where the camera is trying to track a human face and doesn't even get a chance to autofocus because the subject doesn't stay still long enough.
Video 1: 6 shots in regular lighting
Video 2: 6 shots in bright lighting
Link to gallery of all 6 shots (hopefully with EXIF data retained)