The movement bug is much rarer than I think people think it is. It only happens if an AI with a gun starts so far away that he can't attack or move to position within attack range in a single turn.
It is only as rare as the times you put yourself in that position by those terms.
Trying to engage the enemy in a way that you outnumber them temporarily is part of the play, thinning them out.
Dealing with the enemy in batches works against the flooding of the party, which is a convenient means commonly used in "ugoigo" sequence. You want to flood the player with more than the player can chew in a x turns.
"UgoIgo" is characterized by the extreme weight the initial deployment plays in the final outcome. Turning a position is out of question in most configurations and brings no advantages.
In WL2, it is rather easy to initiate combat on your terms. You can even position every one, then use a member to bait the enemy out of position. If you find a certain npc, you can use the locked on party member as a bait, at the start of the encounter, the npc stays immobile and tank damage. The party behind it line up shots as they wish.
When a wave is composed with 9 by 200 hp enemies, the number of turns to tackle it is easy to figure out. Usually, you cant deal with them in one turn, you force the player to put their efforts on one at a time, therefore freeing space for the other enemies.
When the player puts himself in position of dealing with the wave two by two, it is totally a different story.
That "bug" appears to compensate a structural point.
It is also noted that enemies in general have high speed, helping them to cover ground and close on fast.