So, besides being a Melee veteran, what does Roy have going for him? His last (and only) game came out just after Melee, his legacy (as with all past lords) is nonexistent, and really, he's no more interesting than Eliwood or Alm or anyone else. The only reason I can think of that anyone would want him back is because he was in Melee.
Also, I don't see Ike coming back, either. He's not in style anymore. Awakening sold like ****ing HOTCAKES, and Chrom was vastly more interesting than Ike anyway, so really, again, the only reason he would come back was because he was in Brawl.
How about, instead of four boring swordsmen, we have people that are actually interesting? Fire Emblem games (Awakening especially) have amazing supporting casts, but the rule of importance seems to be the biggest thorn in Fire Emblem's side. The Lords are always among the least-interesting characters in the games because they have to be basically good characters. They can't be overly emotional or weird because they have to be great leaders, so we end up with Marth, darker-blue-haired Marth with a club, red-haired Marth, and so-on. Chrom at least had an emotional breakdown when he saw his sister die in front of him, but grew to be a powerful and just king because of it. I can't remember a damn thing interesting about Marth from Shadow Dragon, or Roy from Seals, either.
SO. Since we're stuck with Marth, I say we put our balls on the table and put in Chrom & Robin as a team. Not only is it not a boring swordsman, it's a double-character AND one of them uses magic. It's a double-character that's actually interesting! Yay! Awakening's rep, without a doubt, needs to be a pair. The whole game was about relationships, be they romantic or platonic, and the Dual Support system solidified that, so it would only make sense that the Awakening rep would use this system in Smash 4.
After that, I saw we forego Ike and bring in either Sothe or Micaiah. Sothe is another ninja-esque character, of which we only have one other half-character, and Micaiah is A. a Mage and B. a Light-Mage at that. No one uses light but Zelda. Ideally, I'd like to see Gaius, but he wasn't super-important, unfortunately, although he was apparently very popular (although while we're making wishes, I'd like Tharja).
So there. Take it or leave it; I'm sure there'll be plenty of opposition to my ideas. This is the internet after all. I'm just tired of passing over one of my favorite franchises because all of the characters are so goddamn boring.