If you remove the top plate and move the U-Bolts apart at the top too, then you have even less lateral support for the spring pack, which means that tiny bolt down the middle of the pack is taking all the lateral load. And that bolt is hanging out the bottom where it can get sheared off. The plates should have lateral spring support all the way up to the axle and that center bolt should have protection. All they'd have to do is run the steel up different lengths for different applications or have fittings to go over the U-Bolts so they are not out away from the leaf packs.

I very much like the idea, but I see some possible failure points that would really concern me. At the very least, I would carry my old stock plates, U-Bolts, and a couple new leaf pack center bolts with me when offroading.