I was just trying to get the videos on HQ and it wasn't popping up. I then went to the bottom of the m.youtube page and selected optimize, once there it will run a test for the BB browser once finished HQ videos popped up. Hope this helps.
Yeah, it would be great if they added the HQ option on most of their videos sometime in the future. I can't read subtitiles without HQ, which is a huge flaw.