1) The echoes for doubleblock is wack. If I fight a mob, and Derdhuin was blocking for me. Normally it looks like this:

Derdhuin blocks a huge grouper's attack against you.
Derdhuin blocks a huge grouper's attack against you.

But after I blind the mob I'm fighting it becomes

Someone blocks a huge grouper's attack against you.

... not important, but I was puzzled until I figured it out :p

2) If I'm thirsting, and walk into a room where somebody is spamming, their spam can get past bloodthirst. (Might be a feature)

Addition: If it doesn't work the first time, reconnect the thirsting guy and try again.

3) With balance of the sisters, if you get disarmed and try to rewield certain combinations, you will get the 'xxx does not complement your secondary weapon' - message. However if you remove your weapons, and wield them in the standard order you can use both.

4) I'm probably wrong here, but when I practiced shield cleave, the skill seemed to work lesser the higher my percentage got.