Having people suddenly transmogrifying on you in the middle of combat can be a jarring experience to say the least. With the old legends of werewolves usually having people shift at night, or times of the month uncontrollably; turning into ravenous monsters that only crave the flesh of their fellow men. However when happening upon these monsters they will most likely have already changed. Depriving us of that "wow" factor you get when shit gets way worst for you in a fight. Now werebears on the other hand have a different legend about them. They are warriors "blessed" with the ability to change into monsters by Odin himself whenever the need arises. Resulting in a sort of "upgraded" werewolf that isn't changed because of circumstance, but because its a focused warrior that needs a little bit more aid in tearing your head off.
werecat sounds even greater