Kiddman,
I have heard everything on your list, with the exception of the Magico horn, and I agree that these are well designed systems. But, entirely free of tonal coloration? No, they all have their characteristic sound. With the Classic Audio gear, I like both the reproduction gear and their modern fieldcoil designs. I think that we disagree more in terms of degree than anything else.
It is also, to some extent a matter of taste. While I really like the speakers mentioned, I have my own particular preference, which is for a bit warmer sound and less of a hard edge to the initial attack of the note than speakers like the Everest and most of the TAD drivers. You are correct that these speakers do not have the characteristic horn-type colorations (honky, or upper midrange peak, or shouty quality), but, they do have their own characteristic sound, like all speakers. I have not heard these in my own system, but, I know I could easily live with any of them and could probably tune the system to better fit my own preference.
I do think you have made a very good point that there are horn systems with quite a different set of characteristics than what is considered the weakness of horn systems. To say that "proper" horn systems "sound sweet, smooth yet detailed and dynamic" is something we agree on. The difference we have is on a matter of degree and what constitutes the best balance of various characteristics. That is where the "art" comes into play--good engineering gets one most of the way, but, tuning a system, even if that means deviating from supposed technically correct approach, is important for that last measure.
I will probably never have a chance to hear the Magico horns. If you have personal experience with them, I would welcome a brief description of their sound, particularly, how they differ from the sound of Magico's conventional dynamic speakers (a sound I particularly hate--very dry and brittle sounding).