Scouts are not the strongest early game infantry, Traitors of Rohan are. A good Rohan player can easily push with a couple of traitors and Gamling, and massacre your scouts.
Gondor Soldier spam with a little bit of hero/archer support also beats them, because of the formation. Gondor can also do a quick cavalry rush, which is extremely effective against Isengard.
Orc spam is free, and used correctly can get any resource building when combined with Tainted Land or Eye of Sauron, and Wildmen stealing resources is not enough to stop the orc spam, Isengard ultimately loses out. Once the Nazgul hit the field, its probably GG for Isengard.
Dwarven Guardians win against scouts easily, especially Iron Hills and Ered Luin. With a little support from Bilbo its no challenge at all to defeat scouts.
Finally, both scouts AND Wildmen are extremely weak to a quick cavalry rush, which has been mentioned earlier. Wargs are not a suitable counter to this, because they can be easily killed by pikes, which all factions but Isengard can get very easily. Wargs also lose to both Gondor Knights and Rohirrim of the Eastfold in a 1 on 1 fight. You are also not taking into account that many players choose to spend most of their starting 1k on Bill Ferny and his level-ups, to give them an advantage in early fights. This does not leave them with enough money to get the Wildmen Hut, or any Wildmen, and if you choose to go for Wildmen instead of Bill, you are left without your scout hero, and will probably lose your first encounters against the enemy if he got his scout hero. Simply put, Isengard early game is weak against all factions, and especially weak against Rohan and Mordor.
Now, this is not much of a problem against Gondor or Dwarves, but it is a serious problem against Mordor and Rohan. Instead of nerfing them even more, just make the scouts a wee bit cheaper, and weaker, to contend with the early game spam. Same with Wildmen and Wulfgar. Finally, add a cheap Wildmen Pike unit to counter early game cavalry rushes.
All of the things I just listed have been performed either by me or against me, in at least 50+ games on both GameRanger and Tunngle. With the new economy system, Isengard is even weaker then it was before, and something should be done to marginally improve their early game. I understand that they are supposed to be a bit weaker early game, but it is too much currently, and something should be done to give them at least a fighting chance against Rohan and Mordor.