lets look at the issue from a different perspective.
the first principle of audio is do no harm. when evaluating a speaker system, one approach is to try to detect flaws. thus, select "average" to mediocre recordings for that purpose.
if you can listen to any recording , even one of poor quality without running out of a room, you probably have found an "all around speaker". thus the quest for an all around speaker might be to seek one that minimizes unpleasantness. while i admit this approach is the antithesis of the conventional way of thinking, it certainly keeps you from suffering when listening to "bad recordings".
are there any speakers that come to mind ?
i lived with one for 7 years, namely, 2 pair of stacked quad 57s. i don't recall ever being displeased with a recording played through that system, which also included the original quad amps, a mac c22 preamp and a thorens tt, ortofon arm and cartridge.
my motto: judge a stereo system by what it sounds like with the worst recording, not the best recording.