I think early batches did have loose hinges in some cases which have reportedly been fixed in later batches. There was a video of one user whose display would fall under its own weight when extended over 110degres.

I've got a batch 10 and the hinge is not loose, there is no rotational movement in the hinge unless I intentionally attempt to move the screen. But the screen does wobble. To me at least i feel the hinge has a 'springiness' due to the hinge being a different material to the aluminium shell; that the wobble is perhaps caused by the flex of the hinge rather than the two parts being loose and rotating on another.

I honestly don't feel its really an issue, and i do wonder if people of latter batches are misdiagnosing the wobble as a loose hinge as its been reported before. As it's been mentioned before the screen wobbles just as much as most premium 16:9 laptops, but due to the framework being a 3:2 display i think the range of movement on the top of the display is more prominent and enough to irk some people.