It's something I'll think about, anyway. I put it as Druid to show their deeper connection to animals, but I might consider -2.Only two things I would change would be to tone done animal companion a bit. If it is leveling with the Beast Warrior, I'd suggest druid-4, possibly -2. Animal Companions are mean.
I think you misread Extra Natural Attack or Multiattack. Extra Natual Attack gives you another attack per round (using the full attack option) with your primary natural weapon i.e. two bite attacks per round or three claw attacks per round. Multiattack reduces the penalties you get from your secondary natural weapon (using the full attack option). But yes, the Multiattack feats would also be useful to this class.Second thing would be looking at Extra Natural Attack. Read the Multifighting rules, they are quite nice and already balanced. Giving these as bonus feats would be easily understood for this class. Also, one can take those lines of feats before the Beast Warrior gives you the benefits form Class Abilities.