Fighting with Isengard against Goblins is one of the hardest match-up's in the game. Isengards strength is based on strong units and heroes, not to mention an incredibly powerful lategame. But these abilities are obscured by Goblins massive spam at the beginning of the game.
Isengard suffers against any faction that can easily spam and harass, so first you have to be able to defend your base from the masses of incoming enemies. Goblin Warriors are cheap and also very fast which allows them to spam very easily and effectively without having a great loss in their economy. Isengard however, have strong units which are expensive to buy and have very slow build times.
There are a lot of strategies you can use in this match-up. A good strategy to stop goblin spam and to make your enemy change their strategy is to get a Warg Sentry to defend your Furnaces'.
Warg Sentry Strategy - Creeping
+>+>>>
Description: Build your first two Furnaces in the defence range of Fortress, and build two other Furnaces hidden somewhere nearby (not too far away, as you must not waste time at this stage of the game). You now need to make an Uruk Pit next to your Fortress and then after a Warg Sentry between two Furnaces.
You will be able to get a battalion of Uruk Pikemen very quickly due to a strong economy. After your first Uruk Pikemen, you can either choose to buy another battalion Uruk Pikemen to creep another Warg Lair, or some Uruk-Hai to start harassing your enemies tunnels.
You must be careful about two important things:
Don't let Goblins creep steal you! Make sure you are keeping an eye on your creeping at all times.
If your enemy sees you're building a Warg Sentry, they won't waste too many Goblin Warriors on your base. Instead, they are likely to expand with Tunnels to get Half Troll Maraunders as soon as possible. So after creeping, you must make sure you harass your enemy's Tunnels. I also recommend getting some Uruk Crossbows as they are useful whilst fighting against Goblin armies. When you can afford to do so, build a second Uruk Pit to increase your production or a Warg Pit if you see your enemy is spamming Goblin Archers.
Overview: This match up gets slightly easier for Isengard as the game progresses. Isengard has the strongest army and great economy powers, so you can recover very fast against the Goblin harassment.
The only problem Goblins may create for you is Drogoth. As mentioned earlier, Goblins are very cheap, yet very effective harrassers. This means they can keep a lot of pressure on you while at the same time having an extremely strong economy. This means there is a chance you will see Drogoth on the field by mid-game. Isengard have trouble countering Drogoth because their Uruk Crossbows are expensive, and have a slow reload time.
A great way to take him down is Wormtongue. He levels up very fast and becomes very useful when you get the level 6 power; 'Back Stab'. This inflicts poison damage to Drogoth, and combined with a couple of Uruk Crossbows and Lurtz, Drogoth can be eliminated within seconds.
+
>
>
