im going to have to agree with the OP. the dog is just fine in the game but when it comes to taking on a jug it shouldnt win so easily. considering the jug is a 10 ks and the dog a 5 ks it should definitely take more than 2 bites for it to kill a jug.
if ur a jug maniac all u have is a knife and have to stab the dog more than once to kill it. if ur the assault jug u move super slow. upside is u have a gun and can actually shoot the dog but it still only needs to bite u 2 times.
if u really think about it on average it take about 3-4 bullets to kill a player but once they have jug armor it take like 50 bullets or so to kill them but for the dog it goes from one bite to kill to 2 bites to kill.