Thousand strikes on 10, two weapons on 12 basically kills ALL enemies with on application of the thousand strikes. Exception are the hardest bosses, they go down only 2/3 with that.
With the charge attack, I could do 1500 points of damage in a single critical (and I did not even think a lot about totaly maximisation), so I assume a "good" thousand strikes could deal out around 2000 points of damage (normal attacks would be 250ish to 500ish).
I found that with level 10 life-leech & level 10 bleed normal enemies died in one or two simple hits most of the time... I never put more than one point in whirlwind & rush attack.
Bosses are very easy with level 10 fatality, though.
