The WSJ has an interesting question,
Is more plaintiff-side work on the horizon for BigLaw?
The query stems from an observation of substantial profits by large U.S. firms using alternative billing arrangements for plaintiff-side antitrust cases. They don't foresee doing personal injury or products liability plaintiff work, but tax and customs cases using contingency fees may arise.
Although the diversity of litigation might make for a more interesting workplace, it would be one heck of a headache for conflicts checks.