As topic says, I find my Hoglan is so slow in terms of attack speed that the mob moves out of the way before he can finish the swing. Even then when he hits he does like 1 damage least with my char, MIGHT be the lv diff thou.
Ai fixes are coming in 2018. Level difference does destroy pet damage, outside of Hunter/Schwarzreitter/Cataphract and I suppose Falconer the companions are pretty much just there as an aid to lower level characters.