Druids Should Get Increased Die Steps like Monk

[HalfOrcBeautyQueen]

...as the title says,

Druids should get increased base weapon damage dice steps for their natural weapons.
This benefit would only apply while in animal form.

I think getting an increase every four Druid levels would be about right. Similar to the Unarmed Strike feat:
1d6 - Monk level 1
1.5[1d6] - Monk level 4
2[1d6] - Monk level 8
2.5[1d6] - Monk level 12
3[1d6] - Monk level 16
3.5[1d6] - Monk level 20

At end game you're only doing 1d10 as a Winter Wolf.

At the very least, if this is a balance issue, tweak the Natural Fighting feats so that each time you purchase the feat it increases your Natural Weapon die step by 1, as well as give you the doublestrike chance, so if you took all 3 feats you would have 2.5[W] + 18% doublestrike.