Re: Changing the direction of knockback???
I generally treat it as a +1/4, costed the same as Does KB. One really useful attack is to toss in a vacuum grenade, which removes all the air from a room and pulls everyone in toward the center. From there, with a pile of prone opponents, your teammates let loose with their own AOEs and Explosions (now that everyone is neatly piled) or normal attacks.
If the original attack does enough KB, you even get velocity differential KB damage. Mr. 1 is 3 hexes from attack center, and takes 4" KB. Mr. 2 is 4 hexes away and takes 6" KB. Now they slam into each other for 10d6 KB damage.