Unbreakable units that cannot flee - Can they manually flee?

Can players manually force a unit like the Slashers to flee by pressing the flee button?

Yes, they can.

So whats the difference between pressing the flee button and automatically retreating ?

From personal experience, since their morale is typically higher and they're more evenly matched against the foes that will pursue them, manually fleeing units will regain composure more quickly. That's about the only difference really, and I don't think it's even a direct effect. Just an end result

Yea, I was hoping for a dev response, but its true that a "controlled" flee has much better chances of a quick recovery.

I've used it often when I have my LINF slightly overextended and they need to fall back behind my HINF momentarily to reflank.

Its not without risk though. Specifically fighting near the edge of the map turns a short flee into a full retreat. Also, depending on how many units are targeting you, fleeing in a very unexpected direction can occur. It has to be used carefully sometimes.

Since recovery is based on Moral, and you can manually flee at full Moral, you'd recover much faster. They might get a free hit on you as you clip though.

There is no Morale recovery when a unit is fleeing/rallying, which is something that will addressed with the new additions in the Morale mechanics. Depending on the Morale stat of a unit, the recovery will vary. Also, when a unit will break another unit, it will gain some Morale.

Flanking and rearing will also be improved...more on that later on..