Since Dire Bears are omnivores, they can't eat Veggie Cakes. I (and many others from what I've seen) think they should be able to use Bee Honey as Veggie Cakes (and/or get some other buffs ).
As honey collectors, they should also extend the spoil timer more than normal creature inventories, increase Honeys stack size in their inventory or something similar.
That way they should become decent boss fighters