The biggest one that needs to come back is the Sniper Rifle head shot medal. Why that was left out, IDK. Halo 4 just got rid of so many medals.
I will admit allot of the spree medals were kind of stupid such as Sunburst (get 15 kills with the Spartan Laser without dying). But we had some ones which should have never of left.
-The shotgun sprees (shotgun spree, Open Season and Buck Wild)
-Assist sprees (Wingman is not enough)(Assist spree, Sidekick and Second Gunman)
-Wheelman sprees (Wheelman spree, Road Hog and Road Rage)
-Sword Sprees (Sword spree, Slice n Dice and Cutting Crew)
-Splatter Sprees (Splatter spree, Vehicular manslaughter and Sunday Driver)
-Hammer Sprees (Hammer spree, Dream Crusher and Wrecking Crew)
-Sniper sprees (much missed) (Sniper Spree, Sharpshooter and Be the Bullet)
Until this morning when I went on Halo Reach for the first time in a while and got a Be the Bullet in my first match, did I realize how much I missed these medals.
A Perfection medal is also something the game needs again. I got my first Perfection in H4 a while back and did not get the same feeling as I did when I got my first in Halo Reach.
These medals need to come back IMO