I'd disagree with the "longs to be free" part. my family had a half-wolf as a pet when I was a kid. it was definitely very different from owning a regular dog, but he never longed to be free.

instead, he actually thought he was the alpha male in the family until we got a book on raising a half-wolf and realized we couldn't treat him the same way you would treat a regular dog. so I totally agree with the "won't have much control" part.

wargs aren't necessarily the same as wolves and D&D isn't the same as real life, but I'd expect it to be fanatically loyal to whoever raised it, plus absolutely impossible to control if the PCs treat it like a dog (which I think they will), or totally cooperative and a badass NPC hunter if they actually learn how you treat a wolf differently than a dog.

also, and I realize this is totally useless information, but my brother and I used to get our half-wolf stoned, and he loved it. he would bark senselessly and fall over sideways.