That is quite a list of improvements and I am really stoked. I know this is a complicated project that is not easy but it really is something the internet needs to break the YouTube monopoly on video content.
I am one of the people that migrated from YouTube due to their censorship. Although I will still post the occasional video to Youtube at some point as Dtube continues to improve I may completely abandon it.
RE: D.Tube 0.5: Big Optimizations