One feature I've always wanted to see introduced into Ace of Spades is bullet drop. The concept of bullet drop is that as a bullet travels, it eventually starts to drop, just as in real life.
A prime example for bullet drop is Battlefield 3, as seen in this video. BF3 got a lot right with bullet drop with speeds, leading shots, and adding a sense of realism to the game.
It adds a whole new dimension of playing. Gameplay is no longer about who sees the other person first and is able to pull the trigger. It instead forces you to think about when/where you're shooting.
If you vote no, please give some insight as to what your reasoning is. This poll/thread is purely for feedback and has no intentions of being implemented into the actual game at the time of writing this.