I had one who never learned to stop bucking me off. My trainer had one she had gone to Europe to buy. After having him a few months, she sold him and bought a thorobred. I think there are great warmbloods out there, they were specifically bred to be good riding horses. But not every breeder breeds quality horses, and will continue to use a stallion with an attitude. Some, not all.
I think much depends on what type of horse you like to ride. One that needs a lot of push to get going , or one that has a lot of forwardness. Some Warmblood crosses are good with Thoroughbreds.
You may be better off not choosing a breed per say. But looking for a good confirmation horse that has talent and is easily trained.
Sometimes some spirit and go are far better than calm and lazy. I can't stand pushing a horse to go. And it's much harder to work with a horse that has attitude. If you can take the horse on trial, even better.