i think that would make a great workbench. my only complaint is the shear size of it. it has a large footprint, including wheel base. it is harder to move because of the length and increased weight.
on the flip side, i have no fear of it tipping because it is wider, heavier and the drawers lock when closed. i had many a scary moment moving the smaller box , hitting a crack in the floor that made the lighter box flex and several drawers start to self open!
Your fears where good founded. Mine did exactly that and if it hadn't have been for my dad and a friend acting fast my crinkle finish box would have fell on its face.
What did you do with the old box? extra storage or did you sell it? I have been debating this, the new colors with the 5 drawer carts has me hoping for new colors in the 72" cabinets......that orange would look nice next to oliver green