That kind of thing is typical GM. They make something overthought, overwrought and unreliable.
The midgate idea sucks too, imo. You can only have a full length bed if it's nice out, not cold or hot, it's not a messy load or otherwise don't want the inside of the truck dirty or uncomfortable? That sounds stupid to me.
Haul a bunch of dirt or gravel and get it jammed in the midgate and there is no easy way to rinse it out without risking wetting down the interior.
I also don't understand how opening the rear roof is practical for an SUV? I guess if you carry alot of trees but you can always lay them on their side for more stable transport. You have tons of moving parts, leaks, rattles, electric motors, huge weight penalty for not alot of benefit.
Simple works best. Get an SUV or get a pickup. You try to mix the two and you get impractical. I don't want to flip down the rear seats alot much less a whole midgate thing. What if it rains on you? I guess you drive around with a giant hole in behind you?