Here's a link to the history of the Canadian Pacer from WalkersWest. http://walkerswest.com/History/CanadianPacer.htm
The Canadian Pacer had a huge influence on the foundation of the Tennessee Walking Horse.
The Narangansett Pacer (now sadly extinct) was also a big influence in the Walking Horse breed.
There are gaited Morgans and naturally gaited Appaloosas. Chief Joseph of the Nez Pearce tribe owned the most famous one.
It has been my observation down thru the years, that the Morgan and Appy folks intentionally tried to breed that gait out these horses because it didn't suit THEIR needs.
That is how I view the Canadian Pacer. People tried to breed the gait out of them for their own self-serving wants.
I feel myself heading for the soapbox on this one, so I will quit opinionating while I'm ahead