I see NO difference between the first and second video of that chestnut horse...really, what's your point? He was still strung out, and hollowed, as well as resistent in alot of areas. I think it's more a case of the bit they work him in, does not work well for him; some horses just can't take a certain bit, as it can be uncomfortable for their particular mouth structure, but that does not mean there is not a bit out there for them.
Personally, my mare HATES bitless bridles (I mean the cross over kind like in the vid)...I can ride her in a rope halter, any kind of snaffle, or an english hackemore, but put her in a cross over style bitless and her comfort level goes out the window, so trust me, it's NOT for every horse.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."