Kiddman,
I have heard a LOT of different horn-based speakers. NONE were entirely free of some unnatural tonal coloration. But, that is the case with ALL other forms of speakers I've heard. I live with a horn-based system because, balancing all strengths and weaknesses, I prize what good horn systems can do. My horn-based midrange is very good, in terms of tonal quality and a lack of midrange peak or "shout" when played at lower volume, but, it does develop that quality to some extent when pushed a bit loud. Again, not perfect, but, on balance VERY good.
Perhaps you can enlighten us on what are some of the better designed drivers/horn combinations?
By the way, it is not only horn-based systems that can deliver amazing dynamics and presence that creates an almost "live" performance. I have heard that with both modern and antique fieldcoil drivers in non-horn systems too.