Nerfing J4' armor is not the way to go.
He needs that passive armor. I've tried levelling his W second instead to simulate the nerfs on live, it makes a huge difference. But you know what it doesn't make a difference with? His ganking power. You know what it affects? his dueling power. J4 was never a strong duelist, but his E got him by at least.
As a J4 top main, I would rather have the range on my Flag nerfed over the passive armor it grants me.