I'm returning to this topic because I've been playing F4 a bit more and there's something that Bethesda really need to fix before TESVI: companion AI.
I am going CRAZY trying to adventure with that dog from the trailer. And don't get me wrong, he's a great companion. He's better looking, has way more character, is a better fighter, and is far less annoying in most aspects than the dogs of Skyrim. However, he makes Lydia seem like an ephemeral puff of smoke when it comes to blocking doors and getting in the way!
Whenever you stop, especially when hiding, his default is to position himself right in front of you. Know what else is right in front of you? EVERYTHING ELSE. I have shot him more times than I can count when I was trying to snipe an enemy. He has nudged me off walkways and ledges. I have talked to him instead of opening seemingly millions of containers. I've burst into rooms instead of sneaking into them because I had to push past or jump over him to get through the door. I've blown him up with innumerable grenades because he's charged into a nicely packed group of enemies (incidently, usually scattering the group so the grenade is less effective) . . . ARGH.
I can tell they tried to address this. Most of these behaviors happen when sneaking. His default when not sneaking is to run around like crazy. Which is fine, I guess, unless you DO need to talk to him, specifically to trade stuff with him (like Skyrim, pack mule is the companion's most useful function). To trade, you have to tag him with a conversation, then pick the "trade" dialog. On Xbox, the trade dialog is X button, which is ALSO the button for reloading. I have wasted enormous amounts of ammo by trying to trade with him, only to have him dart away before I can hit X and instead end up reloading a perfectly good magazine or fusion cell.
There are even perks that grant bonuses to damage and carrying capacity if you adventure without a companion. It's like Bethesda is saying "We know they suck. Sorry!"
I've only adventured a little with a human companion, so I don't know for sure if they have the same problems, although I don't see why they wouldn't. The human situational and environmental reactions are well beyond the two or three "Would you look at that!" we had in Skyrim, so that at least is a big improvement. Still, until they improve at LEAST locational intelligence and add some control over combat tactics, I'll be sticking with "Lone Wolf" (wasting perks in the process).