I've always felt a penalty try was problematic; the referee having the power to
give a team 7 points based on subjective view. I think we've all seen too many
questionable penalty tries awarded.
Perhaps a better solution would be for the referee to award a choice of free
kick on the 5 metre line, a penalty kick, or a 5 metre scrum, with an added
yellow card for a particularly grievous offense, such as a high tackle. This
would force the team awarded the penalty to still score the points for
themselves, and perhaps be less controversy for the referee.