The only way i've been able to deal with a Troll now is to eat Stamina Food and Dodge roll into him every time he swings. Don't be afraid and you'll take them down just fine. A knife in their back works great too, but they get pissed and will attack almost right away, but you will still have time to dodge.

As for fulings, i'm not sure what to do about them yet, other than ranged attacks for days.