Followers

[cromcrom]

That's why I make a distinction between followers and companions.
Followers should be very basic things you have almost no control over (attack (my target), stay). They also should be pretty expendable.
But followers would add some great gameplay features/deepness:
Recruit local wandering people, that will give you a bonus to skill if they stay with you. Tame wild animals, followers could be gained from reputation, buying them, quest rewards, some specific skills for some specific followers.

For example, after a character enters the spirit world, he manages to attach an owl spirit to him. This owl spirit would be immune to normal attacks, and grant the player some special powers, like seeing in darkness, mana regeneration boost.
For example, the PC could come accross a wounded warrior. if he successfully heals him (success or warrior die), the warrior will offer to join the player. This warrior might be quite feeble, and would attack the target of the player only. Nothing hard on the AI. PLayer could dismiss him anytime through dialogue.
Some more, the player come across a wolf pup. If he gives him meat, and tames it (through skills or whatever), the pup will turn into a wolf. And so on.

So, followers should be a light enriching feature, on the contrary of companions, that are usually deep complex heavy things.