While I agree that FZero might be mildly important, I'm not so sure that it's enough to warrant another guy, especially ANOTHER SWORD USER. Though I will also agree that FZero is probably more or at least equally well-known as Mother. Star Fox is around the same league, too, actually.
EDIT: To add a little to Sol's stuff up above, I'd have to agree with most of your statement. I remember that Sakurai was disappointed that he didn't have many new IPs to work with. I think from that, we might be able to guess that new stuff was important to him and the series.
However, about the Dixie-Kiddie idea, it was actually somewhat original. He had them not as an Ice Climber deal, but with one riding on top of the other, being able to switch who was on top or bottom, and the attacks were then decided by the height order.
EDIT: To add a little to Sol's stuff up above, I'd have to agree with most of your statement. I remember that Sakurai was disappointed that he didn't have many new IPs to work with. I think from that, we might be able to guess that new stuff was important to him and the series.
However, about the Dixie-Kiddie idea, it was actually somewhat original. He had them not as an Ice Climber deal, but with one riding on top of the other, being able to switch who was on top or bottom, and the attacks were then decided by the height order.