Currently, retreating is extremely slow and clunky. Units will try to create a formation and then move at the slowest unit’s speed… to save themselves. Of course what usually happens is that most of them are picked off and die.
The game lacks a formation/option that allows units to move at their maximum speed, regardless of the other units in the group, and without traveling in formation. They could just end in a default formation at the final destination. Please consider adding this.