Wait, are you telling us you have never used it with your gladiator? If not, what kind of answer are you looking for with this question? You have either:

a. yes, it is useful for hurting the enemy; or
b. no, it is not useful I have never used it after X rank.

Are you trying to ask whether it helps tanking, or the damage it deals in comparison with other gladiator skills? Your question is so vague I could also ask:

Light Slash: Is there any use for this at all?