The stronger the mind and heart, the more necessary a strong, well-conformed body is to contain it- the saddest thing I can think of is a horse that has the passion but a body that just won't hold up. But there's a difference between a horse that has a strong enough body and a horse that is strong enough for what they need to do, if that makes sense.
I agree, some conformation 'faults' make the horse much better for a certain discipline. I've thought about this a lot, lol. Technically, a horse that's level would be ideal, right? But uphill horses are better for jumping/ dressage, and more downhill horses are better on the other end of the performance spectrum- I've noticed that horses with low-set necks are generally better mountain horses, too. 'Perfect' is relative to what you do.