Well, i am not a specialist in history, however i think the agoge wasonly to spartan citizens.
The "Perioikoi Hoplites " were not Spartan citizens, so tech shouldn't affect all Hoplites, only Spartiates.
Decreases the cost of tech as it no longer affects hoplite citizens.
EDIT: Spartan champion are supposed to be the strongest infantry in the game (spearman). Macedonian Champion Silver Shields are equivalent and without the training time penalty acquired with "agoge" tetch.
My proposal:
Increase the health to 30% and give a 10% attack (it seems fair historically) and increase the training time to 15%. The cost goes back to 500f / 500m
See also D2856.