I am a little frustrated by the path finder in combat. It seems to take the longest route thru all of the AoO's of all of the enemies to get to the opponent directly ahead of my PC. WTF!! Also, sometimes PC's take off on a tangent when just moving in a straight line and end up getting into deep doo-doo while the rest of the group ends up some place else. Is this a problem with the AI or is it planned that way? The battle in the swamp is hard enough (but not impossible) with the addition of the sea hag and her cohorts without having every enemies on the screen take a shot at the character before he/she gets to the designated opponent.
I think you can press "Alt" before moving, to see what route your character will take and whether he risks any AoOs. There's nothing much we can do about the pathfinding, it's hardcoded in the game engine.
If you click on a monster to select that monster for a character to attack that monster, and you are concerned the character will take a path to the right [for example] and the character will take AoO attacks as the character moves to the right of the monster, instead, you can click to the left of the monster outside of its AoO area and when the character gets to that spot [to the left of the monster], then, click on that monster for the character to approach the monster to the closest available spot to have the character attack the monster where the character avoids moving to the right of the monster and will not take those AoO attacks.
Ya, I have found you can "drive" a lot better by taking 2 or 3 short moves instead of just 1 big one.
Pressing ALT also allows you to designate what path your PC will take by setting waypoints. Double clicking on your final destination or attacking at the end of your chosen route will send the PC along your chosen path. EDIT: this also shows you if your PC enters any "threatened" areas (for AoO's). But will not tell you if the enemy can actually make an AoO. Watch for flat-footed foes, they cannot make AoO's. Most, in my experience, don't have the combat reflexes feat, and therefore can make only one /round.