One shall stand, one shall ball.
I expect in this case his attack naturally carries further right as he as he steps into the attack so you rolling left probably takes you past the attack's active frames while going right takes you kind of in line with his attack lets him rotate toward you a bit more.
Generally speaking it's best to dodge towards enemies with polearms like spears or halberds unless they are specifically sweeping it horizontally, thrusts and vertical chops track a little better so rolling forward and ideally past the enemy will serve you better.
I'll say it's more possible now than it was back before the reduced the stamina costs of Ultra Weapons. :v
Generally speaking it's best to dodge towards enemies with polearms like spears or halberds unless they are specifically sweeping it horizontally, thrusts and vertical chops track a little better so rolling forward and ideally past the enemy will serve you better.
Quote from Opium:
They said a heavy weapon can do it in 4 hits, but is there a heavy weapon in existence that can be swung four times in that short window? I don't even think I have enough stamina to swing a heavy weapon 4 times.
I'll say it's more possible now than it was back before the reduced the stamina costs of Ultra Weapons. :v