why are Percherons so plentiful and popular in North America?
Not 100% sure about this one. My cousins have several percherons that they trail ride. They seem to have better movement than alot of the draft horses with a super quiet, easy going temperment. I grew up riding percheron crosses, the draft gives bone and an easy going temperment, the lighter horse more athletisism and less bulk, with more stamina. Done right I love a percheron x thoroughbred or arab, etc.
Don't have much experience with canadian horses
Are Canadian Warmbloods as foolish (see above prejudice) as European ones?
I havent known many 'true' warmbloods to give you the most educated oppinion. We did have one hanovarian/thoroughbred mare(registered canadian warmblood) that was trained in dressage and could jump anything you pointed her at. We did lots of trails and even a compeditive trail competition. She definitely was not "foolish".
What do you all expect when you read 'Sport Horse'?
Be wary of this term, its used widely and can apply to any number of things. Often it applys to draft crosses (friesian x, thoroughbredx, etc)
'all TB's have poor feet and no shoulder'
Not true. There are 6 thoroughbreds on the farm right now, they all have great feet, good shoulder and are super athletic, but they are fairly light boned(compared to draftx and warmbloods)
From what you describe, I would look for a draft cross, as you have had before. If you find a good one it would be able to do everything you describe, be tall with good bone, and have a smaller price tag(usually) than a warmblood.