Poor design is rather vague. I recall some complaining about the power connector on labtops was mounted directly on the motherboard meaning accidental pull in the power cord could break the motherboard, a much more expensive repair than simple change of connector. But, although everyone can agree that this is suboptimal - or poor - design, almost all models do this to save space and pieces. So the manufacturer was not liable. "Poor design" may be a feature.
"known sub-standard components" - what does this term mean? How do you evaluate a component to sub-standard? Manufacturers may choose to use a sub-standard component to offer a cheaper product, and you as a consumer decide whether to buy sub-standard products. I think there is a quite large margin before such claims can be made successfully.
And bad packaging I think is part of the assembly. And normal handling conditions? Yes, but they do disclaim liability for wear and tear due or excessive use.
I am not saying that you cannot claim the warranty in these cases, only that it is vaguely defined and they have more money for lawyers.