Battlefield 4 has a lot of new features and improvements when it comes to knifing.
- Different skins can now be unlocked and used to replace the regular knife though they function exactly the same. (Machete, Shank, M9 Bayonet, etc)
- Knife can no longer be equipped for more then a couple seconds
- Players can no longer knife slash 
- Enemies can have takedowns performed on them from 360 degrees 
- Victims of Takedowns can not be revived
- Counter takedowns have been introduced, allowing players to reverse a takedown with a button icon
- Knife takedowns can also be performed in water