What do I like most about Robin?
That’s…a hard question to answer. Which is strange, because she was my third most wanted character for this game, and Fire Emblem is one of my favorite video game franchises out there. I suppose it’s because out of all the potential FE newcomers for this game, Robin was supposed to be the audience surrogate, in a sense, you, guiding the player through the world of Fire Emblem Awakening and providing them a way to save its world. Chrom couldn't do that for the audience, he was the Lord that everyone knew and love, and would become the face of the army. He was just the guy you looked at and followed. Lucina also didn't outright reveal herself until much later, and much of her characterization is drawn upon by the Hero-King Marth, an existing FE character and ancient Lord. But Robin is the character that is most relatable to the average player, and just about nearly everything that happens in the story is related to her somehow, whether its from cataclysmic events in the future or through victorious means achieved because of her tactics. Even though Chrom was supposed to be in every battle, it's explicitly clear that every battle in the game was won because of Robin's tactics.
In terms of game-play, I like Robin because of her capabilities as a Magic Knight in her default class (Tactician). I've always been fond of Magic-users because in real life, that’s the class that I would want to become, and swords are some of my favorite weapons in anything ever. In SSB, every character we've gotten so far was a male Lord who primarily (and in some cases, only) used swords as weapons, and despite the fact that there are much more interesting weapons to choose from in that series, we were limited to only these characters, lessening the appeal to the Fire Emblem series. Imagine if we only got Chrom, outsiders to this series would look upon the characters and scoff at what they just saw, saying “Three blue-haired swordsmen?! What are they, brothers, or is everybody in that franchise the same type of character?”
Robin can re-class into virtually any class that is possible for her gender (females can’t get male-only classes like Warriors for example), obtain any of their skills, and support with anyone and everyone you can recruit. Chrom can support with only a limited amount of people, and he has a small class set comparable with every other character. This makes her the most important character in the game IMO, and up there along the likes of Marth, considered by many to be the face of the franchise.
Her character design is also really nice. I like the textures on her cloak, the three-eyes of Grima motif on her sleeves, and the use of black-and-gold as the cloak's primary colors. She’s also very attractive, though I’ll admit this as a guy that M!Robin’s not too bad-looking in Smash.
Even though it's been a month after her reveal, I'm still ecstatic that Robin is an actual playable character in Smash.