I guess this will put COCO in perspective.
These are the leading class action lawyers in the country and I doubt they would invest in a massive case like this unless they were very sure of a big payday. Like most class action cases though, they will get hundreds of millions and the people who actually were hurt will receive some worthless coupon or something. This case is really totally inappropriate for class action status, as individual questions predominate over common questions. You can't just file a case and say "They are a bunch of crooks. Pay me." , which is pretty much what they have done. The NYSE will claim, and rightly so, that each incident is different and has to be looked at individually. Hence, class treatment is inappropriate.
In the Nasdaq class action there was a pattern of abusive behavior in keeping spreads wide through conspiracy. So that common element was more imnportant than each transaction, because it basically infected each and every transaction. Here, no one is claiming every trade or even most trades were rigged.