There is not a lot of scoring in soccer, of which, it is estimated that the average amount of goals scored in a European match is around 2.5 goals, and about 7% of those goals scored over an entire season, come from the penalty spot. Additionally, about 75-80% of penalty kicks are converted, so that, in a game that is low scoring, being rewarded with a penalty kick, is hugely influential in the result of any given game; and thereby, not too surprisingly, there are players that employ theatrics and trickery in order to procure a penalty kick, over and above, that split second decisions, about whether a penalty should or should not be given, is not always that cut and dry for the referee.
As currently constructed a penalty decision has a huge influence on the outcome of a given game, so that, dubious or not, questionable or not, when a penalty decision has been made, it is highly meaningful. At the same time, some referees will be reluctant to call a penalty, especially in games that are tied, or quite competitive, because they do not want to see the game settled on a penalty decision, when there is still time for the game to be decided through open play. The very best workaround for the way penalties are currently constructed in soccer, is to subdivide penalties into major and minor, in which major penalties would be ones that to the referee are absolutely clear-cut, with no equivocation in the referee's mind, that a player has been clearly fouled in the penalty area, and therefore that penalty should be treated as it is currently, with a spot kick 12 yards away from the goal line. On the other hand, for infractions that are not as clear-cut, and are questionable at least on some level, these would be designated as a minor penalty, but still subject to a penalty kick, because the foul occurred within the penalty area, however, the spot kick, rather than being taken from 12 yards away, would be taken instead from 18 yards away, which is the very outer edge of the penalty area.
The distance for the newly designated penalty minor, would be six yards further away from the current penalty spot, or an increase of 50% in distance, so that in all likelihood the amount of spot kicks that would be successful from that distance would drop to somewhere around 45-50% because of that distance. This new designation of a penalty minor in soccer would be a fair solution to the current problem of games being decided over fouls which are questionable to begin with, and having this replaced instead by a penalty kick which has a much less likelihood of succeeding, would be a reasonable solution. While, no doubt, with this rule, there would be more penalties called overall, that increase would probably be relatively slight; yet, the outcome of having many more penalties kicked from 18 yards out, would mitigate the extra penalties called, and make for a fairer outcome.
While soccer is not known for making any dramatic rule changes, the best way to implement this rule, is to try it out in one of the lesser leagues, or during exhibitions, so as to see how it plays out in the real world, and then have those that manage the sport to vote upon it. It would certainly seem to be a change whose time has come.