lv 150 mobs +

why are the mobs so out of balance. i mean heck there crazy strong. from lv 142 down they dont do that much damage. but 150 up there crazy. This makes it tuff for most classes to lv up the mobs str should only be 5% stronger than the last lv but def can be higher AND hp as well. but if they kill you in 2 hits or less thats not much fun unless you find some way to make it a bit more even.