No problem :)
I forgot to mention length of cannon bones, and amount of bone! I knew I'd forgotten something.
A short cannon bone is good. A long one is bad. You want a horse with sufficient bone for its mass, not one of those US halter monstrosities with stick legs and enough muscle to beat a beef-breed bull for meat production (we have those here too, it's not just the US... sigh, what are the halter judges doing to the breed?), and not something so thick it's coarse.
I haven't even gone into pastern length and angle but I will tell you this. A shorter pastern will be stronger, but will have less shock absorbing capabilities. A more upright pastern will cause a jarring ride, whereas an extremely sloped one will cause a smooth ride but is a lot weaker and more prone to injury. You want a happy medium, the angle around the middle ground between the vertical and the horizontal, and length enough to absorb the concussion but short enough to be nice and strong.
IMHO probably 80% of the stallion population could be gelded, in any breed, and it would be no great loss.
That's all my opinion of course but it's based on what conformation traits are likely to cause unsoundness in a performance horse and what isn't. And any riding horse is a performance horse in its own special way - even the pleasure trails horses! The majority do a lot of miles. That's why soundness is so important and we should breed towards the traits that promote it, and away from the traits that will potentially cause damage in the long run.