No, I think if anything, the effects are being understated.
BP has no really viable option for capping this leak, which is a mile down. Drilling a relief well is a very long shot that might take months to accomplish. Meanwhile, we are entering hurricane season. A big storm could conceivably push the oil around the tip of Florida into the Atlantic where the Gulf stream could pick it up.
The claims process could go on for decades, just as happened with Exxon Valdez, except this has the potential to be much larger. That happened in a remote area of alaska. This threatens trilllions of dollars of beach front property, businesses, marine industries, even shipping into the Mississippi. ships that are contanimated by running through oil have to be cleaned before coming in.
I would not be surprised if BP and Transocean do not survive this. We are looking at $150 bbl oil and $5 gasoline.