I absolutely love the idea of a ground execution... However maybe make a struggle option for the person who is near death? Depending on the person's HP, the struggle will be easier or harder. Someone who kills their opponent with 100% HP will ground execute faster than someone with say 30%.

Idk. I like adding extra mechanics. :3

That being said though, I dont' know how they could add ground executions and keep the game-play intact with the revive system.