First off, great progress! I haven't checked in on this thread in a while, but I'm glad I did!
Now to be to the brass tax... There's not need to hover over the bar for that long, it tends to make you over think and most times fail the lift. I practically run at the bar, get set, get my footing correct, deep belly breaths, and rip that bar up!
Another thing that I think is hindering the bar speed, is that you exhale all you air out when you start to scream at the beginning. Get tight, and stay tight throughout the entire lift to ensure lockout. I would also work on telling yourself to pull your shoulders back, this is needed at lockout.
Another thing that jumped out at me was looking at the 21 second mark of the video... You dip down really low, you ascend without taking the weight with you (no leg drive), then you commence to start the deadlift with the ALL upper back. This is a recipe for disaster down the road, you NEED to drive with the legs, then let your mid-upper back do its thing towards lockout.
These are some of the keys things I took away from dissecting the video.
Cheers and keep killing it brother! LEG DRIVE!!!!