Looks like Rumsfeld took some flak from combat troops while in Kuwait about inadequately armored vehicles. Perhaps you recollect I have been talking about this very problem since before the invasion.
No reason for command detonated mines to seriously injure a soldier riding in a standard sort of mine resistant vehicle. Even the Israeli RAM would give ten, twenty times less injury compared to a HMMV.
http://www.israeli-weapons.com/weapons/vehicles/light_combat_vehicles/ram/Ram.html
Too many photos to post. Same website I posted earlier, a page on this class of vehicle. Machine is armored only where the weight will protect the crew. The running gear, engine, and transmission are designed to protect the armored crew compartment by absorbing the explosion. Engine is an air cooled Deutz.
Interesting vehicle. Israel has had a lot more experience in urban combat, looks like they've put it to good use.
IMHO, the HMMV is being misused, it wasn't designed for the role we've given it in Irag.