Well…
Puts on reading glasses
"Lucina is a clone of Marth, meaning her moveset and animations are primarily based off of his. In a Miiverse post, Sakurai explains that "even a small difference in abilities" gives a character their own roster slot, citing Lucina as an example. In her case, the most obvious difference between Lucina and Marth is that her sword does the same amount of damage throughout, while Marth deals higher damage, knockback and hitstun when hitting with his sword's tip. Additionally, all her attacks do more damage than Marth's sourspot attacks and comparably do less damage than Marth's sweetspotted attacks, making Lucina do more damage over time when compared to Marth if all their connected attacks are sourspotted. These traits make Lucina's moveset a lower-risk, lower-reward version of Marth's.
Because of the lack of a tipper, Lucina plays as a more conventional combo-to-KO character who relies on racking up damage to high percents before finishing off her opponent with a strong attack; conversely, Marth can secure early KOs through careful spacing and tipper smash attacks, while suffering from lower damage racking capabilities due to his weaker sourspot attacks. Lucina is an arguably better rushdown character since her attacks do reliable damage all the time, while Marth relies on punishing opponent's mistakes with tippers in order to earn low percent KOs."
- Whoever edited the Smashwiki page