Theres just no justifaction for the new mobs health and resitance.
A game is supposed to be FUN!! Crouching down and shooting the same mob 480 times while it floats in circles moaning is NOT fun, it requires hardly any skill on my part and not much concentration either unlike 2.1 which was much funner and even harder because you would always go close to mobs and look for cover don't ask my why its just something no one does anymore.