Wrath+Flashing Blade+Aether

So, I pulled a dupe Owain on the Christmas banner, and I'm considering merging him into the older one, but Wrath is pretty rare and powerful. I have a fully merged Tharja running Aether and Flashing Blade seal, and was wondering if Wrath was a good option for her B-slot. Desperation works great, but I'd like to give Wrath a try!