Currently, natural fighting provides doublestrike. I think it would be more effective and better received if it instead increased weapon damage.
Consider, currently the feats that give 2[w] or better are cleave and whirlwind like abilities. Last I heard these don't work in form. Giving 1[w] damage per feat would provide a constant, moderate damage increase that would stack with spell effect increases. You might even go up to 2[w] since that equals cleave but only is working on one enemy at a time. This would only increase attacks by 2d10 damage each rank since you don't have to worry about things like high damage weapons (gs thw with cleave would do more damage by far then wolf with constant damage increase.)