actually, he has not always been just a background character. he was around right before jim henson died, he was the star of the television special tale of the Bunny Picnic, he was one of the main characters on The Jim Henson Hour, and he had big parts in The Muppets At walt disney world and muppetvision 3D, and he had a semi-big part in the muppet christmas carol. although the role wasn't too big, he was featured on the movie poster/ album/ video/ dvd cover, something that did not happen with bunsen, beaker, sam, belinda, betina or peter, characters who were either more major or just as major as bean was in that movie.
another way that he could have been used was in Muppet treasure Island. he could have been a "cute" pirate, using his cuteness for evil, and then either getting kicked out of the pirates for being too cute, or he could have decided to use his cuteness for good.