IMO, there's nothing wrong with the slotted bolting and the gap in the front of the bracket as long as all the bolts are tight. The torsion axle works like a lever lifting on the rear and pivoting the axle down in the front (pivots around the rear bolt). The bolts are loaded in shear (across the diameter) which is the strongest configuration. Bolts up through the frame will be loaded in tension which puts all the load on the threads - the weakest configuration. Just my $0.02.
2015 Rockwood Ultra Lite 2604 WS. Rear LR, large street side slide with small wardrobe slide in BR.
2014 Ram 1500 Eco Diesel Laramie Quad Cab.