She's looking pretty good. Tho I don't see why she needs Swordbreaker. She's already fast and tanky so I don't think Ayra or Karla would be doing much to her anyway. But still, pretty solid.
It's really mainly to help Sheena out the most since her weakest point is Sword units, the most I've honestly seen a Falchion do to F.Corrin was maybe 20 or so, then again I don't see too many +10 Falchion users in Arena
Sheena was the 3rd, and well she needs no introduction she is a pure wall on my team (normally use Atk Smoke over ploy) ever since I got her to +10 I was able to easily beat Abyssal maps