1-2 inches in drop makes a huge difference in the squat as well.
More importantly, is it even necessary for a distance runner or any athlete for that matter to drop below parallel during a back squat? Weigh the cost v. benefit. In the same vein, why do a power clean v. a squat clean? When you try to jump for height do you squat down below parallel?
I think we have to look at the overall strength and development v. the specific sport requirement. Look at the overall range of motion v. the specific sport requirement.
There is no ONE way to do a squat as all variations have value. I could make the argument that quarter squats for speed have a greater value for runners than a full slow heavy squat.
This is how I look at: At first do full range of motion squats. Start with bodyweight, then slowly add weight. The weight doesn't have to be high. The key is form and range of motion. Progress to a 10-15 rep max weight with no breaks in form pumping out reps. Later in the progression switch to a lesser range of motion with heavier weight. Focus on the speed and performance of EACH repetition. Reach a 4-6 rep max weight, but each rep is performed as it's own event. Down, Up with explosive intent, Breath, repeat.
PS: You don't have to do crosshit to learn proper squats....lifters have been doing proper squats for years before crosshit existed.
Alan