With this reforged weapon...

When it comes to her defensive spread, I would prefer not to have her def lowered especially since it is a super bane. And having more spd will help her with the doubles so I would recommend the +spd/-res. 28 res after the bane is still pretty good if she needs to tank some mages like Reinhardt.

I can also say the same for Corrin. He needs to have his def untouched as he is a melee bruiser.