dude stop useing rolls .. i use just dodges and omg the fights are so fluent
This.
I suggest using dodge almost exclusively, with roll just being an emergency escape move. It's very quick and keeps you at a distance where you can keep fighting. It's great for going sideways around enemies, especially when they attack; you can always get some hits in without needing to close the distance much. It find it feels good too since it seems like the kind of thing a fast swordsman like Geralt would do. Works against shield guys as well.
I'd also advise against heavy attack (especially on harder difficulties) unless you're absolutely certain it's gonna hit. It's slow (deliberately so I imagine), lots of monsters can dodge backwards and it leaves you too vulnerable, especially against groups.
Unpredictability? Well, I guess that's gonna be a matter of taste, even more than the rest of it. I like not knowing exactly what they're gonna do. I mean in the Souls series each enemy has 2-3 very specific animations and very strict behaviour but that's needed seeing as though it's done for the specific mechanics the game is based around.
Groups? I find picking on a target and then backing off as soon as they start to surround you essential. It's not like Shadow of Mordor or Batman which encourages you to go in the middle of large groups. I loved the combat in those games but it's pretty difficult to die. I think it took 5 hours or more before I lost a life in Mordor, even after charging into strongholds, and that was because of an unexpected QTE. TW1 had a group style of course but these two sequels are different I find. Letting enemies get around me in TW2&3 gets me in big trouble.
I agree with you that some animations for Geralt are a bit unpredictable. I simply only attack when I feel I'm sure to hit or I feel that at least if I miss, I won't be in too much trouble.
Lastly, use everything in conjunction with your sword. Potions, bombs, and, mainly, signs. A pack of wolves or ghouls might seem like an unruly pack of unpredictable maniacs, leaping and dodging all over the place but catch them two or three of them with Igni when they're near to each other and hey, presto! Two of them back off, one of them gets set alight, you focus on that one, kill it (or nearly), dodge back, get some room and by that time Igni is ready again. That kind of thing. I think the signs compliment the sword even more than in the other two games.
Not sure what else to suggest. Hope you get a feel for it or at least get used to it so it doesn't hamper your enjoyment of the rest of the game. Good luck.
EDIT: Just seen that you don't use roll much. Good on you