In the latest behind-the-scenes video for Rage, the folks at id Software explain how they created hordes of lifelike, realistic, thinking and feeling enemies for you to tear into little pieces. That's why they build them up, buttercup.
I hope we don't just end up fighting only Authority enemies by the end.
Also, I'm still hoping for a game where enemies will be given procedurally generated AI personalities, like random levels of alertness, fortitude, carefulness, etc. I'm tired of so much shit being scripted these days.
And for animation? Euphoria, or systems just like euphoria, are the way to go for unique game enemies and moments. I'm dying for Max Payne 3 for that exact reason. It's using Euphoria further than any game has before.