Terror wise, it's a similar MO as the Asia Airlines disappearance and maybe the pilot feared being shot down or forced down if he had turned toward a metropolitan area. Maybe he saw that as a negative for whatever reason.
Solution - blame it on human error. Pay $300m to victim families. Been done in the past.
I am not saying this is the case here, but it could be.
But having a rich German kid who was living his dream of being a pilot end it in such bizarre way does not sound as probable in my book.