Oh, sorry, EDIT: I wanted to add that the “one-hit kill” nature could be solved if you had a way to disable the attacks somehow. As with the mammoth – if you properly ensnare it in nets, it won’t be able to use its “stomp” ability (unless in heavy armor, instakill 500 dmg), just the “tusk” attack, which is weaker (but still highly damaging if it hits unarmored men).
There could even be specialized mammoth-hunting gear (super-heavy axes, team spears). Something like adjusted and refined large orc weapons.
