To use a 2-handed sword effectively, you need to pay attention to were you put your character, to hit as many targets as possible with each swing. And as they may move, you have to move too.
I 'try' to use Stun Arrows or Blind first and after that start attack with my 2-handed sword. Or Rush Attack and so on ... Or use Thousand Strikes and the victimes life overcome mostly a very fast ending !
On 7th of february 2015 : I start a new adventure in the Divinity world of Original Sin, it's a Fantastic Freaking Fabulous Funny ... it's my All Time Favorite One !