My suspicions are based around what isn't being said.
Why are we not hearing more from tomnod ?
Why didn't they refute the Chinese theory (would have been great publicity for them) ?
Why haven't the US satellites spotted the debris field ?
Satellite imaging must be able to pick up the debris field, if one exists.
It's not going to be cloudy all the time so over the last 4-5 days there must be 95+% coverage.
To me it looks like:
65% went down near last official contact and has been missed
30% hijack
5% decompression/hypoxia scenario
I think hypoxia is unlikely, as 237 inc 12 crew is just too many people all to have been caught out especially at only 40 minutes into a flight. Just too many people observing too many other people all with a bell curve of physiological responses, and oxygen masks available at arms length.