You may speculate all you want about lawsuits bringing down the price of AOD, but the key reason the price of AOD is declining is poor management, pure and simple. I would not be surprised to see this fund restructured. It's been a disaster and continues to be which is about the only consistent thing about it.
They never filed a lawsuit; they said only that they were investigating AOD (and others) for possible illegal activity. They found none and declined to file any lawsuits. Thus, they did nothing wrong or illegal, so there isn't a sound basis for legal action against that law firm.