I'm assuming that both in here and in the Batman thread the sword they're wielding is not exactly "standard", aside from it being lightsaber proof?
Because a standard blade would have a hard time doing any damage to Vader's armor.
Wolverine does have feats such as knocking out a brick goon from a different dimension with nothing but a wooden bokken sword and a hilt of a dagger (while holding back, so he wouldn't kill him), but it'd still be an enormous advantage for Vader if the sword in the OP weren't able to pierce his suit.