I feel like I'm missing something with Sam's moveset. Againston Very Hard I beat him by taunting, charging the third hit of the chain (the big spin), and letting go when he gets near or dodging out of the way if he does a quick pounce or a kunai. It does good damage and ifbladewolfisn't attacking it will knock him down. Sam actually has quite a few moves that will stagger him, but he's much more aggressive than he is against Raiden. His attacks are uninterruptable and he's very rarely in neutral, and I haven't figured out a way to stunlock him, but it seems feasible with blade mode cancels.Bladewolf
I'm still sort of baffled by him, but I'll put some more time in tomorrow.
That seems to be the case with every enemy in the DLC. At points it felt like playing MGR on fast forward, it's quite crazy. Playing Sam is definitely hard mode.