I think it would be nice for animals to come in from the green mist in packs (for pack animals). Then some equation like per 20 pack animal = spawn 1 predator.
I would love to see the NPC part of this game expanded vastly but nothing like the static spawns that MMOs traditionally have. Even the amazing AI in Darkfall was let down by the fact that the NPC do not roam and still have traditional spawn points (yes I know DF is looking at making roaming stuff but watching paint dry is not pleasant)
Don't forget, they have already said they are add a lot more after the actual launch day. From what I've heard/read they will be adding a lot of "other" kinds of species as well.
I don't see that as a priority when lag is horrid without them.. none the less it is rediculous I can run for an hour and more and not see one animal.
I want to hunt, skin, cook and make bone armour.. its a pain without animals.