Well except it doesnt stop his split push at all, or his illusions being hard to nuke down after heart or that he still gets most of his damage from diff blade. This was just a token nerf to make the whiners calm down.
It nerfs his farming ability and his split push ability. All of his illusions are dealing 25% less damage to creeps, so they are going to farm slower, miss more lane creeps, and push slower.