If you play hardcore, the dog and the support squadmate all have the same statss as in core, so you can kill a player in 1-3 bullets, but dogs, you can't C4, granade semtex, and still need a full clip of an smg, assult riffle to kill and squad mates are even worse, the sponge all you bullets then pull out their pistol and shoot you just before you empty the clip, they are also supper accurate.
I say limit both to 2-3 kills max... And/or reduce their health by a percentage for each kill they make. I don't see them altering either of them in any way... I mean the dog has to be a little over the top.. that's what makes it cool but when you see them getting 4-5 kills when clearly they should have died already is just stupid.