Bill Handel of KFI in Los Angeles said the message from this case is: if you want to murder your child, make sure you bury her in a warm spot to ensure decomposition, then wait a month or so to report her missing. You’ll walk free when it comes to trial, no matter the rest of the evidence.
With a populace steeped on CSI-type shows, juries demand an explicit cause of death now to convict. The standard of evidence has changed. It’s wrong, of course, but it is what it is. Juries anymore are full of people who can’t think rationally. They are swayed purely by emotion and by what they see on TV.
DNA is not a requirement either, but a modern concept.
Add that to your point about EXACT CAUSE of death not being a bona fide requirement, and add it to all that is inadmissable in court, and conviction becomes more and more difficult.
You need to ask yourself, who had the means and motive to kill Caylee?