Whether those penalties match the public's outcry for punishment is ultimately subjective. Even if Holder were to string up BP CEO Tony Hayward by his thumbs in Times Square and give every American a tomato, it may not be sufficient. (Oil execs probably won't see jail time.)
Maximum catharsis is also unlikely for logistical reasons. The administration may be suing the pants off BP for years to come, but in the near term it's also depending on the company to clean things up. That won't stop Holder from pursuing the legal case against BP. But it could cause the administration to tamp down its anti-BP rhetoric in the interests of cooperation.
The timeline of environmental lawsuits works against the plaintiffs, too. It took 20 years for the Exxon Valdez case to reach the Supreme Court, by which time outrage had cooled. People looking for catharsis on the Gulf spill will also have to wait, especially considering that we don't know what happened yet. By the time BP lawyers have exited their last courtroom, some other crisis will no doubt have taken its place.
Slate V: BP's Blame Game