Let's face it, no one has the faintest idea were MH370 is. The present favorite hunch is based on a tolerably credible location based on the mathematical interpretation of a few isolated data points that even a political pollster would find inadequate. Come on Guys, show me a seat cushion, not a dozen reasons why you can't find one, you have been looking long enough to find something even though the search area is large.
As soon as you step back from the bustle and the numbers and ask the logical question "Why?", nothing about a Southern route makes sense in this situation. Why would anyone fly an aircraft towards the Antarctic? Does disappearing quietly make a statement? If you intend to crash an aircraft why wait 7 hours to do it? Why fly out of radar range heading Northwesterly then apparently turn Southerly if you intend to crash? Why would you head South when you could have achieved the same end by heading West or Southwest? How do you explain the actions of the flight crew, was one incapacitated, both incapacitated, hijacked?
Here is a simple question. If I intended to crash an aircraft in deep water why would I turn Westerly when I could turn Easterly and fly to the deepest water on the Earth in about the same flight time?
When I reach this illogical position in my own affairs I throw all of the paperwork in the garbage can and start afresh.