My issue is that, I don't want to play on the easiest difficulty. I like the enemies to be somewhat dangerous. It just feels like a cheap way to make players take more damage to make up for the fact that the number of zombies have been decreased in general.
I realize some people love the excitement it adds. Hell, I don't mind ferals showing up, or dogs, or even bears. But when I hit a zombie biker once, he insta full sprints at me and stunning me, and I'm either locked into trading blows or trying to turn and run while he hits me in the back, It doesn't feel like a difficulty increase, as much as it feels like a message of "see? told you that you didn't need more zombies"