The reason you want controls at the aft end of the the tail is because for things like the elevator, you want as big a moment arm as possible to reduce the force required to adjust the pitch of the aircraft. Similarly, the vertical stabilizers are there to help reduce sideslip at higher speed, since a helicopter can fly in any direction, regardless of the orientation of the fuselage. (Generally for lighter helicopters, the vertical stabilizers are fixed, though the larger ones can have a movable rudder.)
Additionally, having a tail will help you if you need to do an autorotation, as it will help prevent the rotors from impacting the ground at the rear when you flare it right before landing. (Here are some examples: http://www.youtube.com/watch?v=T-5ARzqF3R4)
Disclaimer: While I'm a helicopter engineer, I don't work on the controls, so this may be a bit of a simplistic explanation.