How many Fire Emblem characters are there? TOO MANY.
The Metroid series has made 2 exceptional games, and some very good games... and it only has 2 TRUE characters. Samus and Ridley.
Zero Suit Samus is a joke of a character, excluding endgame appearances she has only been in 2 games, one was just a remake, and the other was awful. She only gets put in smash because sex sells.
I'm also surprised that Toad has never made an appearance in Smash, I suppose the argument there is "too many Mario characters already..." But Mario IS iconic, Fire Emblem is only popular in one country and is a relatively new game to the rest of the world. I'm surprised full on Ganon has never been a non-final smash playable character as well.
I wouldn't mind if they even tried out more experimental characters and dropped them for Smash5 if they didn't work out. Once they've made a character they seem terrified of changing anything, like Ganondorf.