A lawsuit won't solve the bigger problem which is hacking and Piracy. All the lawsuit will do is get damages and that will hurt Sony's chances to recover from this. Sony isn't a saint by any means but who forced them to shut down in the 1st place, yup you guessed it hackers and pirates, they are the real culprits in this mess.
I don't think this has to do with piracy at all. That's chump change compared to what a malicious person could do with credit card info and personal information. Pirates don't even make money from pirating, right? They don't charge for the pirated game. I don't see this as anything different from when hackers steal card info from retail stores or bank accounts.
Sony has been really poor with PR, and I think that is hurting their customer relations the most. They're as obfuscating as Japan was about that Daichii reactor in the first weeks after the tsunami. Is the reactor okay or isn't it? Is it leaking or isn't it? How much is it leaking? Are the cooling rods overheating or not? Not a great way to reassure people.