I'd be more concerned about Bayonetta tbh Corrin looks to be gimpable with his/her recovery. Bayo can slow things down and we don't know what flaw this move has as of now along with her combo potential.. not sure on how approaching would work since the demon smash attacks look like they could shut out everything aside for dash and shield.. in short we don't have a good comparison to her playstyle and can't get a good estimate until she comes out
for Corrin vs Mario. Approaching him/her looks like it might be problematic with good ranged fair, wide Utilt, and a long reaching Fsmash.. though we do have a better projectile and can apply pressure with Fireballs. My guess is that the neutral game is going to be similar of that to Marth but with a longer Fsmash and a potential mix up offensive with Dragon Pin. Corrin is definitely going to be having a tough time recovering against Mario with both the Cape and FLOOD. The only question is if there is a disjoint in Dragon Ascent in the later frames or not..
I will be trying Corrin out once they are available in February