I'm pretty much convinced that Lucina got in as a separate character due to another character being cut. Sakurai said that he cut Shulk because he didn't offer unique, but then puts in Lucina, who is literally just Marth with long hair and breasts. I don't buy his 'Lucina plays differently to Marth' excuse. We know that she was originally planned as an alt costume. I think that a character got cut due to time constraints, or due to third party complications, so they separated Lucina to take up an easy roster slot.
I don't think this is the case at all. If anything, Lucina was added as a bonus, she's not replacing a character. It was never stated anywhere a character was cut, and Sakurai's statement was, plain and simply, Lucina was different enough to get a separate slot. That's it. You've got to twist words to try and come up with this theory that Lucina replaced a cut character, when nothing like that was ever stated.
Also lol at not getting Chrom's name right again. I've seen people mistake Chrom's name for Shulk before, but its not as bad as saying "Chrome."
What a twitst!
In all seriousness, Robin was Chrom's replacement.
I think Lucina was just put in as roster padding ala Melee.
Lol no, you're closer though. Robin didn't replace Chrom, Robin was just plain chosen over Chrom. Its not a matter of "Chrom was planned but not unique enough, we used Robin instead." It was "we considered Chrom as a character, but chosen not to add him as Robin was more unique."
Robin didn't replace Chrom because Chrom was never on the roster. In the planning phase, Robin won out, gameover.