One thing I noticed about this was the absence of the Uruk-Hai scouts, that were featured in the first LOTR film. They had only leather armour on and were extremely fast, covering a lot of ground.
I believe Lurtz led them to find the ring for Saruman. The closest thing I saw of them in the game was the Uruk Cleavers.
Any plans for a 'light' unit type for Isengard? I think it'd help in the early game, to have a strong, fast but un-armoured unit.