One thing that annoyed me was the lack of using dog morphs. And when they did use them it was pretty much fu n and games, whereas wolf form was used in battles often. Seriously, there are plenty of breeds that are superior in strenght to wolves and even leopards. And using a dog morph would have been quite practical in spying situations in public places, you just look like a stray dog, though a very muscular one.
Breeds that are able to kill a wolf and a human if controlled by an Animorph, go Google 'em up, see what I mean: German Shepherd (very common, easy to find, doesnt attract attention, possibly weakest of the breeds I mention), Bernese Mountain Dog (common as well, very strong but not naturally aggressive), Greater Swiss Mountain Dog (great strenght, a rare breed), American Bulldog (common in USA, rare elsewhere), Mastiff (common and a true gladiator breed), Bullmastiff (a bit smaller than Mastiff, common), Caucasian Ovtcharka (common in Europe and Russia. Very aggressive and powerful, used to guard sheep from wolves and bears, also used to guard the Berlin Wall), Central Asian Ovtcharka (a bit rare, closely related to Caucasian Ovtcharka), Kangal/Anatolian Shepherd (very savage, large but agile, these dogs eat wolves for breakfast), Great Dane (common), Rottweiler (very common) and the list goes on and on and on.