I watched the Darko vid and, having also heard the Kii 3s at home, I agree with some of what he has to say (not about the treble sound, but perhaps that says more about my usual speaker/amp system compared to his Kef/Hegel combo). It did make me think though; almost universally, all really high- end, cost no object, speaker designs (I don’t mean in the UK, I mean worldwide) are passive designs or, and this is not uncommon, semi-active designs where the bass section alone is powered actively from its own amplification with the mid and treble allowed to be run passively. Why this is the case is open to debate, some may argue it has more to do with customer expectations and market forces in the super high-end rather than absolute sound quality* - on that account I really don’t know, GT would have much more insight here, but it is true that fully active ‘cost no object’ speaker designs are, almost entirely, configured as passive, or semi-active designs.
* I am reminded of YG Acoustics who used to use a semi-active configuration for their (then) top end design; a built in plate-amp powered the bass section. Subsequently they have reverted to a fully passive configuration and I suspect this had more to do with dealer/customer expectations and YG not wanting to use a third party for their amp design (and not wanting to build their own amps) than it did outright sonic performance. As is often the case, even at these cost levels I don’t think sound quality is always the major driving priority.