The Uruk are some of the most strongest Units in the game. This is by design, no problem there. The problem is that their crossbow units are easily 10 times as strong as some of their other units. Their impossable aim, and fast draw make it impossable not to tank a few hits when fighting against a crossbow unit.
If i want to use a crossbow as a player, and get hit while trying to draw a new bolt, the crossbow gets reset, forcing me to flee to draw a new bolt, or attack using a different weapon.
The crossbow units should suffer the same drawback. It would make killing them a lot more skillbased.
Dodge the first bolt, and keep comboing him to keep the unit from drawing another bolt.
In the renewed version of the mod it should be easier to have the unit show the drawing process aswell, since vanilla skeletons draw arrows in 1.9+ versions of minecraft, so the code already exists.
These changes should make it feel like crossbow units are a bit fairer to fight against.
You can also add a crossbow unique modifier that reduces amount of draw progress lost on getting hit, or adds a chance to ignore it. This way player's can still give their units crossbows that don't reset