Before the Helms Deep Breached fight, power up with all the optional stages. With Felllowship characters, choose either Aragon, Legolas, or Gandalf. With Mordor, choose Lurtz, Saruman, or Worm Tougne. Upgrade each on with damage inflicting skills for Lurtz and Worm Tongue, then use stall skills for Saruman (and vice versa). You now have a key advantage for doing great long distance and close quarters damage to the Elven and Rohan soldiers, including the heroes. However, the advantage can be short-lived since they will block and become difficult to hit later.