Not sure if anyone is interested and I'm not sure if this is considered changing the source code. However, I have made a slight change to the Youtube fieldtype so it lazy loads. I utilize the following code for lazy loading https://github.com/verlok/lazyload
Let me know if anyone is interested. Just by lazy loading the Youtube video and a couple of small SVG's in my footer my page load time got cut in more than half from mid 3 seconds to 1.5ish seconds.