The typical SUV (Cadillac Escalade, for example) used for livery is rated a 6 passenger. However, the common Mercedes sprinter van would be an 8 passenger and it's ridiculous to think drivers should be required to have a CDL with passenger endorsement to drive one.
You're right on, nothing will ever bring those 20 people back. On top of that, the investigation isn't even completed yet. This proposal likely has more to do with the Princess feeling the heat from the families who also blame DOT for the way that intersection was reconfigured.