True, almost any interface that overlaps helpful data in layers or stacks is usually terrible. Hell, I don't even like desktop computer GUIs that allow you to have stacks of windows. I'd rather see one thing at a time and cycle between them. Or have a picker view.
That said we do actually get quite a bit out of that ability to see depth. People who lose depth perception have quite a hard time adapting to the world. And our spatial understanding seems to go beyond our vision. That to me is where a 3D interface might be really powerful. Sometimes things which we struggle to decode in 2D are just intuitive in 3D like knots or the run of wires or pipes.
As I said elsewhere in this thread I think the 3D interfaces that are really going to be powerful haven't occurred to us yet. And I believe that what we'll find in time is that there are things which 3D interfaces are tremendously advantagous for and using anything else will feel like a hinderance. But those will be things for which 2D interfaces don't already do an amazing job.
Carmack already mentioned the existence of "true 3D" content, for which you get a 3D interface whether you like it or not, so to speak, so I didn't go into that.
But making everything 3D, because VR, is as silly as when the gaming industry made everything 3D, resulting in entire console libraries full of games that looked like shit even at the time, pushing 4 or 5 frames per second and having other incredible compromises, when the same consoles are monsters of 2D performance. As nice as it may be to have truly 3D content available in psuedo-real space, there's no reason to insist that when you want to set the shininess of a given pipe that you need a huge skueomorphic switch as big as an old car stick shift that you can visibly pull popping out of your UI or something when all you need is a slider. (If anything, I'd think minimalism in a VR environment is a good idea, both to contrast the other content and to prevent detracting from it.)
I think that's probably the kind of crap Carmack is complaining about. We've already been around the same loop a couple of times already, and 3D, albeit on 2D surfaces, was one of them, so it's fair to look to the past instances of such BS and maybe this time try to move along the curve a bit faster. I'd say that if we can get this nonsense out of the way faster rather than slower, we're more likely to get to the truly useful 3D stuff that doesn't exist yet. Otherwise we risk 3D interfaces becoming something like the Wiimote, which IMHO was actually a really useful tool that has become despised solely because it was badly misused by so many games, because motion controls. (Another example we've already been through.)
One other hypothetical use of a 3D interface is as a way to conceptualize "true N-dimensional" data. A 3D experience indeed doesn't help any rational conceptualize of a rational situation but it might, maybe, allow you to mobilize the unconscious reflexes humans have for dealing with regular 3d space. But all this might also a 90s cyberpunk fantasy.
That said we do actually get quite a bit out of that ability to see depth. People who lose depth perception have quite a hard time adapting to the world. And our spatial understanding seems to go beyond our vision. That to me is where a 3D interface might be really powerful. Sometimes things which we struggle to decode in 2D are just intuitive in 3D like knots or the run of wires or pipes.
As I said elsewhere in this thread I think the 3D interfaces that are really going to be powerful haven't occurred to us yet. And I believe that what we'll find in time is that there are things which 3D interfaces are tremendously advantagous for and using anything else will feel like a hinderance. But those will be things for which 2D interfaces don't already do an amazing job.