I believe a fixed fee billing systems for lawyers would be far superior to hourly billing. With a fixed rate a person would know up front what he or she is being charged for. It would prevent lawyers from upping their fees for services that a client might not want. It would make lawyers work more efficiently working on a fixed rate.
Hourly billing is ultimately better. If you pay lawyers a lump sum, they have the liberty to spend as much time to as little time on your case. You definitely could get yourself in a bind if your lawyers are not honest and ethical. I would encourage all law firms to do this.