Benjamin - I feel that you are being a bit patronising there...if you are going to do so at least back up the assertion with a cogent argument.
Beating the game using horsemen doesn't invalidate the point made that the dragon queens have effectively made equivalent Panzers much better than Horsemen in almost every way. I had got bored with doing CH7/8 but used the dragon queens and a mix of Panzers + 7*/6* dragons to breeze through the chapters with revives only needed on the 3 obvious points - I reckon I would have needed a lot more revives with Horsemen.
I used to agree that the Horseman could give greater gross damage throughput and took the time to measure it over 500+ activations but as the advantage was around 65% the advent of the dragon queens effectively nullifies the only real edge that the Horsemen possessed!
As for raids.....
In the last GW my post panzer alts found they lagged way behind my pre-Panzer alts when I ran panzer teams vs. Horseman teams whereas in the previous raids there was close to parity between the two methods.
In your mono-white example an equivalent Panzer will still beat Faith especially as Faith will reduce HP so survivability and the unreliability of the Horsemen make using them against Horsemen flaky - especially when you CAN use a strong coloured Panzer/Shooter in those whereas not with Horsemen!
(Have you tested that the damage is amplified as you do know we are not actually spinning reels in the game?)
I was a bit of a fan of Horsemen prior to the new GW rewards but PM seem to have decided to weaken Horsemen for some unknown reason