Not sure what a class action lawsuit is going to help? Maybe those who weren't under warranty when the part failed?
There have been 5 or 6 iterations of the part(s). VW has obviously been trying to fix the issue, and I'm sure if you were to call VWA outside of warranty and bitch they would likely replace the part at no charge. They fully understand this is an ongoing battle. I've had service advisors tell me I'll need 2 or 3 replacements over the life of the vehicle. The real fix would be to design a part that doesn't leak. VW uses plastic rather than metal for many parts for thermo conductivity purposes including the oil pan.
Most class action lawsuits result in a much less than reasonable outcome like a $25 coupon towards a replacement part, $100 off a ticket to Hawaii but only on Wednesdays, a $5 rebate, etc. Never have any of the ones I've ever been a party to provided me any real "relief". Mostly they are never worth my time and postage stamp to submit a claim.
The only proper outcome is a fully covered replacement (parts and labor) WHENEVER it fails, in or out of warranty and replacement with a part that won't likely fail within 10 years or more - like a real metal water pump. Out of all the cars I've owned,. the only water pump that failed was in my then 17 year old Camaro. So I'd expect that kind of longevity in a replacement. But, as I've said, no class action lawsuit has ever really provided me any real value. They are usually less than useless. Just money for the lawyers.