Porcupine structure
I am not saying this is perfect but I do think it is better at mimicking the natural thing. Personally, if I had a lake to place such structure in I would use green or black PVC and there would be multiple sections that went back and forth and in and out and every which way. Enough cover to not only attract crappie but to get the bait fish and other food supplies to inhabit the structure at the same time. Could even take some sort of shallow blade and cut groves all up and down the PVC to give places for moss, algae and other plant material to get a hold in. Cut big holes in the PVC pipe for bait fish to hide in and crayfish.
Is everything I see straight up and down to limit lost jigs and lures?
I know, I know nothing about attracting crappie to structure but I do know a little about attracting plants and critters to it. Just me 2 cents I guess but I think there is room for a lot of improvements that will improve even the commercial one's production a lot.
I love taking my kids fishing, now if I could just manage to fish at the same time.