I understand the need for the game to get harder as you get stronger, and for it to not be too hard while your character is still weak. However, rather than just change the type of enemies to be found in the world as the player gains in strength, why not just change the enemy A.I. as the player gets stronger. What I mean is, say you are weak and walk near a mammoth. Why couldn't it be set up to where the mammoth leaves you alone (unless you attack it)? And then if you are stronger, then would the mammoth attack you if you got too near. (this does not include "bosses" that you need to fight for quest completion. They would need to level as you do to keep the game playable)
Why does it have to be a mudcrab at t = t1 and a mammoth at t = t2?
In a real world, animals and creatures won't suddenly start appearing on a continent just because you get stronger, yet in a real world a very powerful enemy might completely leave alone what amounts to an insect before it (and conversely try to destroy what it considers a threat).
Obviously it's probably too late for a change like this, but what do you guys think? (hope I didn't screw up the poll)