I dislike horses built downhill too. Because I hate feeling like I am riding downhill, and it seems like when I ride a horse that is built downhill, I also feel like I am riding downhill.
Also, I dislike heavily built horses with fine bones and small feet. Small feet is probably my #1 pet peeve, especially on a big horse.
Now I love Arabians because they are well proportioned and sound and weight carrying for their size. But something like a halter QH with fine bones and small feet, that really annoys me, because the poor horse doesnt have the frame to carry his weight.
I love heavily muscled horses, so I should really like QH's, right? But the breed also has some of my biggest comformational pet peeves, so I like some of them but not a lot of them.
Basically I like a good, strong, sound using horse that can ride the trails for hours and hours and stay sound doing it!