I've considered this.
If I were going to remove it, I'd rig some sort of alternate support.
A dry bag that would always have the same solid stuff in ti would be the foot brace, and maybe a line of 6" PVC tubes with foam end pads that wedged in tight to help prevent the deck squishing down. the perfect rectangular custom box would be ideal, but would need some serious fabrication skills. Maybe plastic welded panels with foam top and bottom to make it fit tight and slide.
Did you get the Hard Hat that they make for the rear hatch?. I assume the one for the Karma Traverse would fit it. Are those standard now?
For what its worth, the traverse holds more gear and is way more nimble, if not quite as fast.
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