I see where you're coming from, but Lucas and Zelda only use elemental magic in their Specials (barring one of Lucas' Throws). And Robin is known for using elemental magic. Zelda has her sparkles (I suppose that could be Light Elemental magic, but Robin doesn't have that) and Lucas has all his PK Love effects (which is psychic energy, I believe). I think that if Robin's magic was only represented in his Specials it would make him more like Zelda, Lucas and Ness. Robin would have Fire, Wind, and Electric elements in his Specials only, just like Zelda (Din's Fire, Farore's Wind) and Lucas (PK Thunder, PK Fire). It would make him more like Ness because he uses Elemental Magic (so to speak) for his specials and weapons for some of his other moves.
A pure magic Robin would be similar to Lucas and Zelda, but it likely wouldn't be too similar. I like a Stance-change Robin or a sword & magic Robin, but pure magic is probably better to help flesh out the FE representation.