1d10/2d6 is weird too 2d10 versus 3d6. Scaling weapons across that barrier acts odd. A small claymore will do more damage than a large one. Maybe 2d6 weapons should be called out as going to 4d6. I don't see any spots where that looks like a problem.
Maybe just say "double the base damage dice"?
I like this. Seems to be the easiest way to keep the curve intact, while avoiding any problems that adding a flat damage value would cause.
Revised. I think this is better, where better = More Blood.
More Blood for the Blood God
Violence cuts deep and life is short. All base damage dice AND all Bleed DCs are doubled.
(Eg a Mace would go from 1d8 lethal to 2d8 lethal, a Great club would go from 2d6 lethal to 4d6 lethal, and a Throwing knife would go from 1d4 lethal to 2d4 lethal. A successful attack doing 7 damage with the Bleed quality would have a Fortitude save DC of 14. A successful attack doing 12 damage would have a DC 24.