Everyone has their own preferences and my opinion is just that, what I prefer.
I personally, feel a windshield is only half of the protection when touring- AKA riding on highways and interstates. I want a fairing to keep the cold air as well as the wind off me, for that adds to my fatigue, and also to reduce the rain and road spray on my feet and legs. As for summer heat, I can switch to a lighter or vented armored jacket or take the car, as I do in the winter snow and cold!