spoilers:end of spoilers
I do agree that the sequence of events here are a bit odd. If New Order really is gone for good then the main consequence of the battle is that All For Shigaraki has been weakened to a still unspecificed degree, which is significant in it's own right, and extending a deadline that was already a bit iffy. But introducing a cool new character with a cool new quirk only to get rid of both and pretty much nip the idea of help from international heroes in the bud feels like a bit of a waste (though introducing MORE heroes at this point in the story when many are already complaining that certain characters deserve more screen time than what they're given probably would've been its own issue).
With the spirit battle being almost certainly assured I wonder if there will be a split between Tomura Shigaraki and Tenko Shimura beneath that pit of spirit hands. Something broken that needs to be put together into a whole again. What that whole is and how dangerous it is remains to be seen.
I wouldn't mind a smaller more low key arc at this point. Give us some training at the school, the band enacting their plan to lift the civilian's spirits, Deku getting a new costume and some important talks here and there before the class rushes off to the hunt for All For One and the rest of the league.
And yeah, giving the two bit thug a name and then possibly not having more involved with the story is a bit weird, but not something outside of Horikoshi's previous subversions.
I do like it when superheroes/-villains fly with wings instead of just nothing. So yeah, it would be a cool permanent addition.