Let's start the legendary banner with the worst Corrins

The thing about bad IVs is really just about how much it bothers you. -atk/+spd is still very strong because a bladetome corrin on a flier team gets +30 attack when fully buffed anyways. The -3 attack seems quite insignificant now, and the +3 speed will always be very useful. I can tell you this, but it's up to you whether or not that little -atk is enough for you to not want to build her. If it bothers you too much, then there's no helping it, nobody will blame you. If you can live with it, then congratulations, you have a top tier unit that becomes insanely, game-breakingly powerful on a flier team.

If you want her, build the +Spd one, with Life and Death 3 a Hone Fliers buff and a Blarblade+ she will still reach 52 attack and 48 speed +6 extra damage (+possibly 12 more with a fortify fliers buff) and room for fine tuning with a seal.

So yeah, while -atk is not optimal, she overkills many targets anyway. Merge them and have fun

Just wanted to confirm what Aiumi and Nezyrael said. I use my -atk/+spd S!Corrin in my flier emblem team with Blarblade+ and she is monster! Merge her and add a summoner support and you won't regret it :)

The -attack one might be salvageable. But I’ve seen a lot of horrid IVs from the pulls people have gotten from this banner. Sounds like it’s going more 5* but less quality.

Build her as Bladetome and that -Atk isn't too bad because you got the +Spd on her. I think Darting Blow is far superior than Swift Strike. You want to increase her doubling potential, especially with Desperation. Most of her damage will come form the flier buffs that add on to her total atk. Since she doesn't have any premium skills to give, it is best to merge her.