For those who have or are concerned about this wobble there is a cheap easy way to compensate for it, I believe. Until I came across these threads I was not aware of this possibility. It does depend on the surface you’re using it on, and in my specific use I have a lap desk that is tilted just slightly towards me, or it’s resting on my lap, or on a pillow on my lap, which all tilt the MKB just a bit towards me so I never noticed this. Also I never go banging my fingers on the upper portion of the screen since light touches are all that’s required; most of the time when I touch the screen I use a stylus or the pencil. Others use the trackpad. Either way there just isn’t going to be much of a wobble.
For any that also had the previous MKB you’ll see how the exterior material wraps over the bottom hinge adding additional support in back. Without that material the hinge would be slightly elevated over any surface as the hinge in the new MKB is. So for those concerned you could purchase a couple of small rubber adhesive bumpers to stick on the bottom of the hinge which would take up that gap when the the MKB is unfolded. That should prevent most if not all of the wobble. I did notice when taking a very close look at my old MKB that the material that wraps over the hinge had a couple very tiny areas on the ends that had frayed. I remember seeing threads here in the past from those complaining about this. As I’ve had that MKB for 4+ years I‘ve not been bothered by it. Apple has avoided that potential issue by having a bare hinge.
There is also a very expensive way of dealing with the wobble. A number of people here in the past had referred to a leather case for the MKB by Pad & Quill, now called Burton cases. The exterior leather forms that additional support that‘s missing from the bare hinge, it also would negate the need for any skins on the surface of the MKB. But you’d be spending about $180.