Ok, a lot of folks seem to be under the impression that I don't want anymore Fire Emblem characters because I don't like the series or don't understand the units, but that is totally not true. I have been playing Fire Emblem since Blazing Sword was released in the states. I absolutely loved the game and it prompted me to search out the Japanese only titles and play those in-between each new release. I just checked my 3DS log, I have over 150+ hours in Awakening. I played through all DLC and leveled my units to 20/20 a multitude of times in order to get every skill on every character. Want to verse my team? You better be prepared, since they carry mostly Breaker, Vantage, Counter and Galewind skills, have max stats and completely overpowered forged weapons. In the two GBA versions, Blazing Sword and Sacred Stones, my units are unstoppable in the arena since I have the best stats, supports and weapons. (I do not like the way they split the classes with Fates, they should have kept every class in both versions, ugh) Now that is out of the way...
I personally feel that Marth and Ike are the two most popular lords in Fire Emblem fandom, with Ike probably being the most popular. They represent the lords of the series well. The Fire Emblem fan within me has a better suggestion than to keep adding lords as fighters. Why not classes? Instead of picking a unique character from the series, just use a class. For example, imagine a "Warrior" class was added, and the newcomer was simply "Warrior". I think that would be balls to the walls amazing. My favorite class is the Beserker, but with Warrior, he can use axes and bows. Instead of Robin, I wish they would have added a basic Sage or Druid, that only used magic, no Levin Sword. I feel the Levin Sword defeats the purpose of having a magic user. Imagine they added a General? Or a Halberdier? Dread Fighter? Those classes are the classes I think could bring the most variety to Smash Bros., based on the weapons they use. Hero, Swrormaster and other sword wielding classes are already present with Marth and Ike.
Better yet, imagine a true Fire Emblem stage with Pegasus Knights and Wyvern Lords flying around in the background, fighting among one another and occasionally picking on fighters? For example, if a fighter were to attack a Pegasus Knight, then the other Pegasus Knights would attack that fighter, while the Wyvern Lords would help that fighter. Kind of like picking a side. Castle Siege was the biggest let down ever, but the Coliseum stage was a major improvement.
There are many possibilities for Fire Emblem, but I do not think simply adding lords and avatars is the correct way to represent it.