Neighbor kid shot a monster 8-point in full velvet last Sunday that went down in 30-45 yds, but left almost no blood behind. He hit the femoral artery--no idea where the blood went, but it didn't go on the ground.
No doubt a 3-blade or 4-blade could help in some cases, but there is no magic broadhead that will be perfect for every situation--and there are situations where they will be a hinderance vs. a 2-blade.
Chad