Re: Rear melee take-down not working
Part 1 probably isn't a bug. To trigger the melee animation, you have to be at similar height as your target. In this GIF, your target is high enough to prevent the animation from activating mid-swing.
On #2 - in Battlefield melee is supposed to have two purposes: one is stealth takedowns (for which it does its job well enough), the other is being the last resort weapon in CQC. Emphasis on "last resort" - the weapon that is only supposed to bail you out if you face a weakened or confused enemy. It's not supposed to be the best option available (which would basically be the case in CQC with 1-hit kill). That's what a high rate of fire automatic gun or a shotgun is for.