I would accuse Sakurai of doing so, actually.
His reasoning is all kinds of fucked. Chrom would be another swordsman, but Lucina works because....?
I'm not complaining about her inclusion, i'll probably main as Lucina. I'm drawing the only conclusion I can from that translation. She's a clone, but she's a woman so it's cool.
it's because her character essentially is marth for like half the game