I was looking at this from a programmers view and I think I have come up with the cause of the jerkiness. When moving, the code runs a ensure you are moving forward command and when shooting the code runs a turn to shoot command. If the mob is in front of you and your are heading toward it, this works out fine as both the turn to shoot does not affect the movement command. The issue comes when you shooting an enemy and you move past them which causes a conflict of these two commands. When a shot happens, the attack command forces the character to face the enemy. The movement command can not process unless the character is pointing the right direction so it tries to turn it around to move. The fighting of these two commands every .5 seconds is what's causing the jerkiness.
So, my solution is to disable the turn to MOVE check when an enemy is actively engaged. This would let the turn to shoot command work and the character could keep moving, albeit backwards or sideways. If the player had full axis control as they do on console or computer games, this is how they would strafe and shoot.