It goes without saying that my ideas don´t take care about balance of the game.
Which is also the reason why such a concept will not see the light in the Edain mod. With all due respect, but if you wish to see such a concept or any concept for that matter implemented into the mod, you will have to adhere to the basic requirements. Balance is one of them, besides practicality and transparency etc.
When it comes to gameplay, certain matchups are already quite tough for Isengard with their early game handicap. Gondor with a Gondor Knights rush is one of them. This is already the case with how Isengard is currently designed. It would only get worse with what you suggest to change and not solve Isengard's issues in certain matchups.
I suggest you inform yourself on the current status of the ''meta'' of Edain, and understand the current strengths and weaknesses of each faction on a competitive level and try to shape your suggestions around that knowledge.
Finally, Isengard has undergone quite some changes since their initial release, to the point where the team feels that Isengard is in a solid spot, and that such radical changes are not what is required any longer. I advise small and subtle changes.
I hope you understand what I am trying to say, and I don't mean to discourage you from posting your thoughts. Just keep in mind what I told you. Also, your English is fine.
Kind regards,
Odysseus.