Thanks for the insight. I agree that a 3rd party media provider such as YouTube & SoundCloud has it potential for problems. It's not a perfect solution I agree. I have been toying with re-attaching tabs to different audio sources when a video dies for example. I'm not entirely happy with current results. It should be automatic, which I have a pretty good idea on how to do, but haven't gotten around to implementing yet.
I just checked the competition, they still suffer the same problems you're facing : most videos simply won't load, a lot because they can only be viewed on youtube, some are blocked (for me at least), some are gone.