Since launch, I have not been a fan out player outlines. They are (in my opinion) ugly and distracting from the game. With the release of forge and custom games, there are now tons of surreal maps with stealth and dark environments. Player outlines in these maps not only detracts from the immersion in these atmospheric maps, but completely ruins any chance of stealth gameplay or surprising other players. Infection maps especially are effected by this.
There is a setting to remove outlines already, BUT this is only for your client. If you were to choose to remove outlines in a dark map to immerse yourself into it more, you are putting yourself at a disadvantage, assuming that the rest of the game is still using them for perfect visibility of players.
I propose a toggle in custom games to remove player outlines for everh player in order to enhance the atmoshpere of maps. Give the option to show nametags above the head highlighted in blue/red/any color when the player nears your crosshairs like in previous games.