There is a good solution, namely this, transparency. Just like the law requires manufacturers of food to label what goes into the box, so sellers of aggregated derivatives should label what goes into their CDOs, CDSs, etc. This would enable to buyer to have half a chance at assessing the risk attached. Seller won't do this however until they are forced to do it because they don't want to say what is in the secret sauce. The only reason I can fathom that someone would want to buy a "mystery gift" derivative is greed.
As Warren Buffet says, "I hold my nose and point towards Wall Street."
But the contents of each CDO and CDS was/is completely transparent to the buyer and seller. Maybe the buyers were less sophisticated than the sellers, but that's really too convenient an excuse. The whole CDO construction process was openly called 'Ratings Arbitrage' after all.
I agree that things should be transparent : And so the right thing to do is to force all CDS to clear vs. a central counterparty, with publicly known mark-to-market pricing. Similarly, banks should be required to mark-to-market on an arms-length basis. But somehow this legislation never gets passed...
As Warren Buffet says, "I hold my nose and point towards Wall Street."