I feel your pain with the 2h spam, and know that sometimes it can be overwhelming but here is my tip (which may have been covered but anyway...)
Try to out footwork him (Circle him, weave close and far, feint in and out. Mind the imaginary line that is his range and play there). I have decent luck against 2h berserkers when I dance around and try to slip a quick stab from outside his perceived range. Remember the thrust has a bit more range but you have to be quick. In and out, like a snake. If all else fails, try another weapon. If you are comfortable with the 2h and manual blocking, go for it. Archery? Sure why not. Mix it up. (Range works well against the 2h, even throwing axes or darts. Anything to throw em off.)
Anything aside from a duel server, remember this...teamwork is your strongest weapon. Circle them and don't stop until they become red mist.