I want them to sneak when I sneak. Right now, they never sneak.
I want them to be hostile to anyone who is hostile to the player. Right now, they are only hostile to enemies who are hostile towards them. I have noticed there are times when others are NOT hostile to them, but hostile to player. (I assume this is probably set by a faction added to their alias? Which faction(s)?
The other problem related to combat is they sometimes have to be almost on top of an enemy to realize he's a bad guy. I think maybe their AI radius needs tweaking or something.
I'm trying not to use the vanilla setup because I don't want them counted as an official follower to the player. More like when Delphine follows you to that dragon mound.