As someone who launched the game for the first time yesterday, I definitely agree that the jumping feels like it takes away all sense of tactical positioning. Attacks of opportunity are basically irrelevant because you can always avoid them by jumping, and enemies who are smart enough to do the same make it pointless to try and focus on AoOs or constricting enemy movement with area effects.
No really.
Enemies are so obsessed with hight advantage. Yesterday a ranged enemy took 3 AoO in one turn because he walked away from us to reach a higher position.
It could have been 4 AoO but one of my chars had a ranged weapon equipped when the enemy walked by.
The enemy did not even attack me. My AoO slowed him down so much that he did not reach his high ground.
I think thats the most stupid enemy behaviour I have seen so far, together with enemies just doing nothing when you shoot them from stealth.
Prof. Dr. Dr. Mad S. Tist 
