I challenge you to A/B your horns with any model of Magnepan speakers
and see if you still want the horns. Listen especially to voices and
"quiet" instruments.
I've been doing this for several decades now. I like the Maggies if you have the right amp with enough power and decent speaker cables. But they are not as fast or as revealing as my horn system (Classic Audio Loudspeakers model T3.3 with field coil powered drivers for the horns).
Field coils bring speed to any driver that uses them. When you put power through the voice coil of any dynamic driver (and this includes Magnaplanars) the magnetic field sags as the current is increased. Maggies don't sag as much as some other drivers as things are spread out. But its still audible. Field coils allow cone and compression drivers to have the same speed as ESLs and really for the same reason- a power supply is running the motive force.
As far as 'shouty' goes, this is an artifact of distortion. Horns can exhibit it if the throat interface to the mouth of the horn isn't designed properly. These days with computer optimization that really shouldn't be an issue. But the other thing to keep in mind is that older horns are meant to work with amps with a higher output impedance. If used with an amp of lower output impedance it can throw off the crossover point. If the driver starts operating out of band it can make additional distortion. Because the output impedance was highly variable in the old days, older horn systems usually had level controls on the midrange and tweeter to allow you to adjust the speaker to the voltage response of the amplifier. Most people think they were there to adjust to the room but that isn't how it works.
