If your up against a Samurai be prepared to block some hits, because your not going to be going swinging like a maniac.
Orochi parry has been nerfed so hard everyone that uses him just blocks so you don't have to worry about that. Most Orochi's just use Storm rush, you know that back dash lunging strike, all you have to do is block it, whichever side he's holding the blade at is where you need to block. If you can block that and punish them, they might ragequit, it's been happening a lot to me when I'm up against noob Orochi's.
Kensei is just the Japanesee version of the Warden, fast swings and a long blade only difference the Kensei has a Unblockable overhead. But that attack has a lot of start up and if your quick enough you can hit him out of it before he goes unvulnerable or simply sidestep it.
The Nobushi has bad stamina, and it can easily deplete just by doing 2 kicks, which is the move she using to create distance between you and her. Heavy attacks waste to much stamina and has a start up so most Nobushi's use light attacks and bleeds. Be prepared to block a lot of hits and always look out for bleeds. And since she a zoning class you can tell she want to guardbreak so just keep swinging because now swings can stop guardbreaks of any class even the Raider tackle.
I hope this helps, the Samurai aren't op you just need to pay attention to their movements and learn how to block. You can block even when you are exhausted so don't be afraid to play defensive. Just stand your ground, block their attacks and punish them for trying to cheese you.