How do you think the nature of the game would change if the penalty area was a semi-circle or oval instead of a rectangle? Would the game become more defensive or more attacking?
You would have more free kicks from insanely dangerous positions, which I actually think would increase the number of goals per game. Refs may be more willing to call fouls knowing they won’t lead to penalties, which are converted 85% of the time. However, do you all think that teams would be able to hunker down more? Or do you think that changing the size of the box might actually force teams to open up? Or help expose the gaps between the best and worst teams?
There are also a couple of advantages to the penalty area being a semi circle. It would assure every point at the edge of the penalty area is equidistant from the goal, thus reducing the number of penalty kicks that occur from non-dangerous positions at the corners of the box. For example, we frequently see penalty kicks occur against teams who are defending with 10 men behind the ball because a winger committed a non-intentional, weak foul on the top right/left corner of the box. The attacker would not have had a clear goal-scoring opportunity anyway, and yet is rewarded with an 85% chance of making a penalty.
Second, if my math is correct, this would only reduce the size of the box by about a third. That’s a lot, but not entirely game-altering.
It’s fine for the pro level, but it’s not really something that would be easy to properly implement on fields at grass roots and youth levels.
I think the rectangle was chosen because it’s just easier all around for groundsmen at all levels for football.