Back When
One was looking for a new washing machine (before we got the Miele), did some research into uber-sized capacity front loaders. As our previous unit was a Malber that held about that the Miele does if not a bit less, wanted to get something that held a bit more.
The upshot was from every washer tech and information one could find is that far better to slightly once and awhile over load a front loader (within reason and depending upon what one is washing), than to purchase a washer with more capacity than one will routinely use.
Rationale is simple: front loaders wash and spin their best at rated or near capacity. Loading a 15lb washer with 8lbs of laundry can cause all sorts of problems down the line.
Depending upon how the drum is designed, if the load is too small it may not be "lifted and dropped" , but slosh about from section to section between fins. While this may result in a more delicate wash action, it could give less than great cleaning results.
In terms of balance,distribution and extraction, again depending upon design and how the unit is programmed, it could spend ages trying to balance a small load, and even then may not suceed. Then the unit will either spin with the unbalanced load (lots of vibration/shaking), or in some cases (again depending upon the programming), simply not spin at all.
Excess vibration/shaking is not good for a front loader, especially if it happens all the time as dealing with unbalanced loads caused by under use of capacity. Even with the best built machines, things will start to work their way loose if subject to this treatment over and over.