Originally Posted by ShyGuy

No scenario can match the envisioned potential cases of onboard fire, pressurization issue, smoke, etc.

The actions of waiting until a frequency handoff, turning a transponder to standby, turning initially left of course for a certain distance, and then another turn after several minutes southbound over the ocean, never communicating any intent, no mayday, no attempted change in altitude/climb/dive. It's fairly obvious these were deliberate actions by someone on the plane. Eliminating passengers (which the police investigators seem to have already done) and the culprits become the two upfront. Given their personal histories, the CA is suspect.

Originally Posted by abelenky

I don't think the new home simulator evidence, combined with the other facts (waiting until a frequency handoff, transponder to standby, multiple course adjustments) really closes the case just yet.

This scenario relies on Zaharie Shah being a successful, happy, healthy, well adjusted person, with no financial troubles and a good support network around him, having some sort of invisible, persistent, silent psychotic break over the course of many weeks: From whenever the idea was originally formed, to rehearsing it on his simulator, to actually executing it several weeks later.

That kind of invisible, un-triggered, long term mental crisis is almost unprecedented. There's been no evidence found of problems with Shah's health, finances, marriage, career, political views, etc.
Coupled with the total lack of a suicide note or manifesto, it is really difficult to accept this theory, and also makes other theories, however far-fetched, look a little bit more plausible.