Just a small trick

When your hunting hard monsters such as titans etc. pin them down on the walls. as they do have pathfinding around rocks/tree's and buildings. they wont go around eachother. so pin them down in a streight line along a wall and only one will fight you at a time.. Can be handy in most times.

Also: Lornar's passage like.. the 2th zone down from there has those nasty Rock trowers you can get passed without being knocked down. let one (for axample a monk with rebirth) pin them down at a wall. let them trow rocks at you into the wall. and let a Elementalist AOE kill them with ease.. (best and most simple way to kill them and get passed). just some idea's will post more if i find some.

Cheers.

Yes, that is nice and nifty. You can exploit the poor pathfinding in other ways too.

The mobs will try to use the direct way to someone. Knowing this, you can easily block their path in a whole. Get a tank to stand exactly around a corner and get yourself in a position behind him and around the corner. The mobs most of the time won't be able to maneuver around the tank. The only time they can is when they lag past the tank.

(like illustrated in the attachment - stand like this and the pathfinding will start glitching like a gone mad "bunny" on world domination tour ;))