I doubt that high efficiency speakers and good low level detail are absolutes. It’s likely more important that things like the amp being a good match to drive the speaker impedance, the system has good resolution, and that phase coherency and overall clarity of the speakers are excellent, along with a suitable room acoustics, etc...all are still significant factors regardless of the speaker efficiency.
Audio is complex, and it’s rarely as simple as isolating one parameter and calling it good. There are always good and bad examples and pros and cons with every principle you can name, and every choice you can make.