I don't like a weight vest for quad dominant people. If you're quad dominant and you add a weight vest, you're going to be even MORE quad dominant in my experience. Due to that additional weight, you're going to push off using your strongest muscles even more => even more knee bend and quad overload.
I don't have a good comment to make, except that I can see your arm action looks "weak" and I think you'd benefit from a hell of a lot more hamstring strength looking at how you run: it looks like a bit of "collapsed" running to me (too much knee bend for my liking) but I could be wrong.
You also don't have enough "nerve" or "desire", at least comparing to myself - whenever I sprint I do so like my life depends on it.