Percentage of gross annual earnings from the year of the crime.
0-100% sliding scale decided by a judge based on crime severity.
Let the public veto the fine (back to a new judge) via referendum if they deem it too lenient. Rinse and repeat. Let the public get some punches in because corps have been swinging down at us for over a century.
The fact that this is "too democratic" to be realistic is a sign of the times, imo.