Looks ok to me. Those slotted aluminum pieces have been pretty sturdy in my experience. They also bolt together tightly, so it shouldn't wobble too much.
The only thing that I could imagine failing would be the plate on the bottom. It you're planning on having that support weight you'll probably want some crossbars. If it's a thin sheet held on by a few bolts, the bolts are liable to tear right through it if enough weight is put in the center.