micro-contrast as a term is both nebulous as well as useless. even a cursory look at an MTF graphs tell you something that I thought was fairly obvious to everyone; sharpness is simply contrast. for any frequency of line pairs, or size of an object on the image field, there is a contrast level (though it can change based on orientation, I will grant).
"micro contrast" as most people use it just betrays that they do not understand that they are looking at high ~20 lp/mm contrast and low astigmatism. of course, these days with improvements in manufacturing as well as the ability to correct distortion, vignetting and color shift in post, it's possible to make even cheap lenses with low astigmatism and decent contrast.
3-dimensionality is similarly nebulous but you might be interested in knowing that that discussion has been around for more than 100 years. in a previous life, the exact same thing was known as plasticity. the best explanation I've heard for that is it's a combination of lighting and a len's transition to OoF that cause this. Telecentric designs tend to do this more often than symmetrical designs. A good example is how much more often you see this effect from the 50 Lux ASPH than from most other 50s. Of course, that is a lens that does not follow the traditional double gauss, symmetrical design and is in fact a rather significant deviation.
