This is a discussion I have brought up in the past, as well. A that time, Wayne emphasized maintaining the distance between the driver/port/baffle and the corner. Also, the gap between the wall and and the sides of the bass box was important.I have looked at modifying the bass box and modifiying the mid-horn. When I calulated the final dimensions of the bass box, it became a very squat structure and would have placed the tweeter very low (which maybe isn't a concern).
I finally settled on adding "wings" to the bass box to increase the effective width to match the mid-horn, giving the speaker a more uniform appearance.