D7100 sensor is 3.9 µm and has a dynamic range of 13.7 vs 14.4 D800 and 13.6 IQ180
It looks like new technology is pushing the quality obtainable with small pixel pitch..... the limitation will be diffraction.
It will be interesting to see what the limits will be in terms of resolution. Diffraction is relative to the format size, so it is no worse on a small sensor than on a large, just open up the aperture. Concerning depth of field vs diffraction it's a zero-sum game.
My guess would be that the limit will be in the optics and the required precision for those to get such high resolving power. Lens mount could have precision issues too, causing widely varying performance. It seems to me that the medium format has a better tradeoff in terms of format size to be able to squeeze out resolving power from optics. That is at least what I see currently, tech camera lenses resolve more pixels inside their image circle than the best tilt-shift lenses for DSLRs.
I've thought about the reason why that can be, I think it's not so much about that Schneider/Rodenstock would be better at doing optics than for example Canon, maybe it's even the opposite, but Canon need to make different design tradeoffs including stronger retrofocus (there's a mirror there, but even if mirrorless color cast which we accept in tech cams would not be acceptable in a 135 camera so retrofocus it is) and support larger aperture. A tech cam lens designer can give-a-damn about large aperture and care less about color cast and design just for high resolving power for a specific working aperture.
We'll see those high resolution sensors in cameras quite soon I think, and in the longer term it is best to outresolve both lens and diffraction with the sensor so we maximize what the system can get, and we don't get issues with aliasing and moiré.
From a tech camera perspective though I'm a bit worried that those sensor designs actually worsens color cast which makes those successful highly symmetric wide angle lens designs impossible. The trend in medium format has also been towards smaller pixels and worse color cast, but I'm glad than the new sensor in IQ260 actually take a step backwards from the IQ180 and works better with tech cam applications.
However, we see that when resolving power becomes really high the complexity of lens design increases, as we can see in Rodenstock wide angles. Part of their complexity is due to that they are retrofocus to reduce color cast with an IQ180 I guess, but a simple symmetric design only goes that far on the wide end. I don't particularly like that trend either, at some point resolving power is enough for practical image making and I would prefer focus on other aspects of the camera system rather than pushing towards more and more complex optics which increase cost (and weight and reduce robustness) in a more permanent way than complex electronics do. The complex lens designs also often have worse bokeh due to their high degree of correction. I'd like to see the traditional large format lens designs as well represented in the Schneider Apo-Digitar series live on.