I mean, yeah, he could one-shot pretty much everything if he physically hit them with the sword, the problem is survive long enough to close the distance until he can do so, like talking purely from the Arifureta side (as main supporter and because is the spot above Saint Seiya) he would get swarmed by a shower of 6-B attacks (potentially stronger depending on what they decide to use) from pretty much everyone as they are mostly range spammers, and even if he somehow is able to tank all of those attacks he would still have a hard time hitting with the sword most characters (any skill debate aside, all of them can fly and generally do so, with various of them even abusing teleportation to dodge, so Skarbrand would have a hard time cutting them considering his lack of flight or mobility options). So he should probably just stay with Saint Seiya place.