I am guessing it's probably a bit too early to find a decent AI mod; for companions and enemy NPC's?

I haven't tackled companions, but my http://www.gamesas.com/index.php?/topic/1123423-relz-arwens-nv-realism-tweaks/ does improve the AI combat (plus a bunch of other things).

Beside's Arwen's excellent work, I don't think there's much else around yet. You know it's funny, given how atrocious the combat AI was in FO3, I had kind of thought they might improve on it in this SEQUEL, seeing as that's what SEQUELS do, as opposed to EXPANSIONS which just add new content....