The more you look at Gallowglasses the more you can see that they are a very good unit.

There stats before any bonuses.
Gallowglasses.
Charge 8 Attack 5 Defence 0 Armour 2 Morale 0

Now add the valour bonus for Ireland

Charge 8 Attack 6 Defence 1 Armour 2 Morale 2

Plus a master armorer

Charge 8 Attack 5 Defence 4 Armour 5 Morale 2

Plus morale for religous building.

Charge 8 Attack 5 Defence 4 Armour 2 Morale 8

Towards the end of a game they can become very scary!