Pretty awesome! The one big feature I'm missing is comments (Not visible by default, but maybe they could appear from a button at the bottom of the description?) Also, it'd be nice if the time links worked (Some videos have times in the description that help you navigate, especially on full album uploads).
missing comments could very easily be seen as a bonus feature. The youtube comments are pretty much the lowest form of human intellect, mostly racist, sexisit or any other ist coupled with lol's and "work at home" spam. I am happy not to see another youtube comment in my life ever again.
I'm probably not going to integrate comments, but note that you can click the name of the video you're viewing to go to the YouTube page for it if you really want to see comments for it.
Would you mind linking to a video with a time in the description if you have one handy that I can use for testing?