You can get a penalty for a trip while running towards the corner flag with the box packed full of people, yet be through on goal, get tripped outside the box and just get a freekick. Never been right to me.
The original rule makers obviously had a reason for introducing the penalty, it didn't come into effect until 1891, so I assume defenders where just fouling strikers near the goal, rather than risk conceding and were getting away with it, as the freekicks didn't lead to a goal. They didn't zone the area, but we all know you can score from the corner at 18 yards, so a foul there should be a pen and the line has to go to the dead ball line. Its too complicated to change, TAA beats his man on the dead ball line, Nunez is unmarked on the 6 yd line for a tap in, player will just take Trent out if he knows it'll be nothing worse than a free kick.
Its been a part of the game for 131 years, so would never like to see it changed.