Coulson has been in Iron Man, Iron Man 2, Thor, Marvel's The Avengers as a supporting character and he has also been the main character in two short films The Consultant and Something Funny Happened On The Way To Thor's Hammer.
Over the past 4 years this guy has been more or less responsible for bringing together The Avengers and in the end of all things it was his sacrifice that united the broken and scattered team and led them to save the world from an alien invasion by the Mad Titan.
Coulson has become one of the highlights of Phase One and will be missed so it's only fitting that he gets his own figure to commemorate his time in the MCU.