Khoveraki, do you know what a concussion is and how you receive one?
Getting kneed and even punched in the face/head does enough damage let alone the extra force a guy can get behind a head stomp. The temple is a very sensitive spot and a stomp that landed right would very likely kill someone.
And you are wrong in thinking most fans just want blood. People don't watch MMA to see people try and kill each other. This wass pretty damn obvious by the uproar created from the blood at the UFC event in Germany.
People watch MMA because they want to see the best fighters, this can be done without having to endanger peoples lives. It is just like boxing or wrestling etc.