When regular troops lose an assault, they are either totally unharmed, (if they pass morale) or flee, or be destroyed.
Fearless units always take wounds, and if there are multiple fearless units fighting each unit takes the extra wounds, which is counter-intuitive.
Here’s a house rule proposal: fearless units losing an assault should take a Ld check like everyone else. If they pass, they are unharmed. If they fail, they take their “No Retreat” wounds.
Then, fearlessness wouldn’t be a detriment in close combat like it is now.