There are more benefits to high current design than just driving low impedances and it's not just marketing. I don't think Krell, Levinson, Bryston, Arcam amongst others who are high current and some of the finest amps made would agree either that "high current" is just marketing. The higher current allows better control of the driver, especially the woofer, and is better suited for handling quick transcients which equates to better dynamics. Sugden is more of a unique product and not the norm. In some receivers maybe there is some hype. I would use Onkyo as a reference, unless they have recently changed, I guarantee they are high current. Other than Sugden, I can't think of a high end amp that wouldn't be a high current design, just referring to solid state. Also, high current amps tend to have larger power supplies in them. All watts are not created equal.

Don't take my word, do some listening. I think you will find a high current amp will deliver a more powerful and dynamic presentation, much more punch in the bass. and will hold it's own against amps rated with twice the watts using the same speakers. A high current amp in comparison to other designs will sound like the loudness control is on. You will also notice that high current amps will maintain their sound quality better at lower volume.

It is also interesting that some of the finest sounding speakers in the world are very inefficient. So what does that say about your poorly designed speaker theory? Again, Audio Note is the minority and not the majority. Because they decide to do things differently can't make the other hundereds of engineers wrong.