Animals, make some of them travel in packs.

This alone would give more incentive to using armor and would also make the kills more valuable.

Why? because animals in packs combined with a major hit points boost would be difficult to take down. It would take a hunting party.

That wouldn't be to say that no lone animals exist in the world, I just think it would be MUCH better if a majority of them traveled in packs (and double or triple all of the mobs hp....more even...i can 2 shot the highest HP mob in the game and DDT can 1 shot it).