B!Tharja IVs

Definitely not. The good thing about her weapon is that it boosts her atk a ton. The added res makes her tank magic hits better, and with fury she’ll still work wonders.

She's so much fun to use. I'm not sure any IV would really do much to her viability. Even with -spd, her B-slot can really turn the tides of any encounter. Sure, it's a bit situational, but it has saved my bacon on multiple occasions.

Enjoy!

Personally I don't think even the worst IV's are "unsalvageable." -Atk B!Tharja could also run Blade tome to make up for the Atk bane - since her Spd is so high, a properly buffed Blade tome on her will OR (if not outright OH) KO pretty often.

A Res boon also means that she can take a magic hit on retaliation to hopefully dip her into Desperation range. It all just depends on how you build her.