One thing you should consider is the benefit of stretching, why stretch if there is full range and all is well?The reason why you have the fascia in the first place is to increase the mechanical advantage of the muscle providing them with enough intrinsic force to contract, keeping the fascia too flexible means that intrinsic force is lost and the muscles may contract appearing weak. I agree with you that you should stretch but there should be logical reason to e.g tightness

Concerning constriction in muscular vessels, hypertrophy in the muscles as you train may cause that so therefore from your point of view it would be logical to stretch fascia as you train but the question is should you do it before you train or after? If you stretch before you train, you are only stretching within the confines of what is already there however stretching after you train means that you are accomodating more for what is built. Maybe a more logical way to look at it is stretch in the interim as soon as you start weight training not just wait for preexercise moments, the type of training you perform will determine what kind of stretch you need. stretching everytime when range is not affected unneccesarily means you run the risk of putting your muscles in an excessive force production state. I can imagine what that would mean for surrounding muscles who are working in synchrony for movement.

Nice thoughts though...