A common suggestion to reduce the value of the three pointer is to widen the court and make the three point line the same distance all around the court. The thinking is that corner threes are more valuable because they are taken from nearly two feet closer to the net so if we make the three point line the same distance all around the court that will eliminate the discrepancy between the value of corner threes and above the break threes.
Unlike in the NBA, the WNBA three point line is the same distance from the corners as it is everywhere else, so a good starting point would be to see if the corner three is still more valuable in the WNBA. In the 2019 WNBA season the league average was 35.9% on corner threes compared to 33.3% on above the break threes, so corner threes were made at a 2.6% higher rate. Even though the corner three in the WNBA is not shorter, it is still a more valuable shot than other three point attempts. In the 2018-19 NBA season corner threes were made at a 3.5% higher rate. This would suggest that distance is a factor in making the corner three more valuable but it is not the only factor. So what else makes the corner three so valuable?
One of the factors is the types of shots that are taken from the corner - you don’t see many contested pull-up threes from the corner. Last season 95% of corner threes were assisted, compared to 78% of above the break threes. Assisted jump shots are, in general, better shots than unassisted jump shots - last season the league average on catch and shoot threes was 36.7% and on pull-up threes it was 32.7% according to NBA tracking data. The fact that such a high percentage of corner three attempts are catch and shoot attempts won’t change if the distance of the corner three is increased.
Another factor is the geometry of the court. Seth Partnow wrote about this several years ago at Nylon Calculus. Seth found that corner threes are, on average, more open than above the break threes. It is pretty basic that shots that are more open are more valuable. Widening the court and increasing the distance of the corner three may actually result in even more open corner threes because of the extra distance defenders need to cover to get out to shooters.
Exactly how much of the value comes from the shorter distance would require more in depth analysis than this, but widening the court will still result in the corner three being a more valuable shot than the above the break three. The geometry of the court plays a major role and the spacing benefits of simply having a good shooter standing in the corner won’t go away if the corner three increases in distance.