My understanding is so far:
- The content of the image is more important than the execution.
- Stunning photographs can be made with any decent equipment, or at least any equipment up the task
- A better system may help with image quality in prints.
- Higher resolution allows for larger prints.
- MFDBs lack AA-filter. This improves perceived sharpness. AA-filtered images need more aggressive sharpening which increases noise
- Lack of AA-filtering leads to artifacts, but it seems that it matters little in real world images. Stopping down to f/11 or beyond seems to take care of color moiré, based on Lloyd Chambers findings on the Leica S2.
That seems like a fair summary. On the subject of AA-filters, there seems to be quite a bit of general ignorance (not with you) going round, also witnessed by some comments in this thread.
Aliasing is evil, period. It is an unwelcome artifact. Large amounts of money and effort are spent in various industries to avoid it, e.g. sound engineering and other signal processing settings. All discrete sampling at regular intervals will produce aliasing when there is finer detail than the sampling aperture and interval can resolve unambiguously. For that, more than 2 samples per cycle are required to avoid aliasing. More oversampling will help to improve the result even further.
There are several reasons why one may get away with one's aliased output, but without preventitive measures there will always be aliasing present. We can do several things to reduce the risk of it showing as a clearly visible artifact. By understanding the mechanisms in play, we can optimize the situation in our advantage. In general we need to reduce the amplitude of the aliasing component in our images, and that is only possible before it occurs.
MF camera's in general have some characteristics that can help to reduce the risk of aliasing, but they are not immune to the issue. In fact the absence of an AA-filter (optical low-pass filter, OLPF, for lowering the amplitude of aliasing) increases the risk, as e.g. fashion photographers know only too well.
Characteristics that do help are for instance the (>33%) higher on-sensor magnification for a given FOV when compared to e.g. 24x36mm sensors. By imaging fine detail larger, it is less likely to be smaller than the Nyquist frequency beyond which aliasing occurs. The lower spatial frequencies of the subject matter will also generate a higher MTF response, and thus create a stronger signal to overpower aliasing.
Other helpful factors are less DOF, or more diffraction. Less DOF than with smaller sensor arrays will automatically mean more OOF detail. OOF detail will lose some of its higher spatial frequency content amplitude, and defocus thus acts as an OLPF of sorts. A somewhat similar effect can be achieved by closing down the aperture far enough to generate visible diffraction blur at the pixel level. The higher on-sensor magnification and larger number of pixels will allow to create output with less magnification, so the blur introduced this way won't be as noticeable.
Larger files make it a bit easier to attempt and hide the aliasing in postprocessing, although this will always mean that real resolution is sacrificed, because signal and aliasing cannot be separated once their signals are merged. Some loss of resolution is more acceptable when one has some to spare ...
So, attributing the choice of manufacturers to include AA-filters to attempt and avoid public outcry is too simple an explanation. The outcry should be the same for MF users who spent a lot more money on their equipment, if it were not for some mitigating circumstances as outlined above. What's more, cost of large AA filters is exponentially higher as size increases. Try finding Lithium Niobate filters with an adequate (>60mm) diameter to cover an MF sensor array, and you will see. Growing, cutting, polishing,and assembling 2 of those crystal layers is hard. It will be much more expensive than adding a more acceptable size LCD on the MF backs. Again, manufacturers exploit the probability that there are more tethered shooters with MF backs, so they can save a few dimes on a decent LCD for judging sharpness. There is no doubt that they will certainly avoid AA-filters for cost reasons, if they already do it for LCDs.
The absence of AA-filters on most MF sensor arrays is a costsaver for manufacturers, and there are some circumstances why they can get away with it. Unfortunately for fashion photographers, they need to shoot their subjects in focus, and from some distance, which makes it a bad scenario to avoid a lot of damage control/postprocessing.