Here is an article noting many sources saying that malpractice reform won't save that much money. I suspect that it won't save much money, but still think that malpractice reform is crucial to get to both a political deal for health reform, and also to get the docs on board with the functioning in any new system that has a hope of cutting costs, as I wrote a few weeks ago.
And, to reiterate, if you think docs are just money-grubbers and are completely self interested (I don't), this is the best way to call their bluff. If costs don't drop, they will be in a much weakened negotiating position. But, you have to give essentially the full monty reform (like a cap on non-econ damages), otherwise it will be like arguing with 'religious' tax cutters....you just didn't cut taxes enough, etc.