There is one thing that should be mentioned:
Using Take Cover or Take Cover in Place may be sluggish if you are activating Cover using the Quickslots instead of the built-in keybinding.
I figured this out during my Beta TwitchTV stream, and due to the number of posts from other Smugglers / IAs complaining about the delay in activating Cover, I posted the following:
It's in the first paragraph of section 1.
But yeah, your videos are proof of the effectiveness of Gunslinger/Sniper in PvP. Perhaps at level 50 things change, but I personally doubt it. The core mechanics are simple, and work: Take a knee, then take their heads.