He is a face character
All of the unlockable characters in Melee were either secondary characters or characters from series that were not as popular as the others (Fire Emblem)
In SSB, it was the same deal, as Earthbound was a pretty cult game at that point and F Zero consisted of two games as opposed to like six or seven now
There is no reason for Falcon to be unlockable and the only argument the idiots who belive so have is the fact that he was in SSB, which is promptly disproven at any rate if you just read all of this post anyways