Nailed it, especially the point regarding their genders being swapped. If Lucina was male and Dark Pit was female, Lucina would be the one everyone's whining about. Anyway, Dark Pit is an excellent, perfectly natural choice for a clone.
You really shouldn't generalize, I'm not a fan of Dark Pit which is why I wouldn't want him in, but it doesn't bother me. On the other hand Lucina has more of a personality than Chrom and is much more likeable as a character which is why I like that if there had to be a FE clone, that it's her.