Board Thread:Wiki discussions and announcements/@comment-1990160-20140521040036/@comment-4022742-20140523172550

There are diminishing returns though, even by your own numbers seeing as it goes from 50% reduction to 66.7% reduction. That these diminishing returns only visibly show up when you buy more health doesn't change the fact that they are present. After that 200 armor you could go to 300 armor and it would equivalently reward you with 3000 health. But if you'd buy 1000 health instead it would reward you with 4000 health instead.

It's not an illusion of diminishing return, it's factually there. It's also the basis for players to avoid building more then... Was it 240 armor?... to more efficiently spend their gold in relation to EHP.