In my view, there will never be a perfect referees decision on what constitutes a clear penalty. I think sentiment always plays a part. There's no doubt that technology will help and has helped in aiding the referee in his assessment .

However, I think that regular vision checks, physical well being and psychological tests should be done on the referees on a regular basics, to determine and ascertain their general well being. Additionally, new technologies should be invented that can calculate or measure the degree of contact/impact on the 18 box. Like the Infrared that is used in goal line technology. That been said, the referee need to way all these options, before before awarding a penalty.