Personally, I don't doubt the conclusion that the a/c is somewhere in the Indian Ocean, but I am starting to doubt the Malaysian authorities competence and commitment to transparency in this investigation.
That may look like so to Joe Six Pack watching the news and from reading the media. It's so easy for the man on the street to accuse Malaysia as `incompetent' and `not transparent'. Yes, they had made a hash of it initially during the start. But it's more due to inexperience and the lack of any real plan in dealing with public communications. They don't make public each and every detail from the data they have (or been given as is more likely). But it would be simplistic, at this stage, to say they aren't committed to transparency. And wrong to accuse them of "covering up", as some Chinese families accuse (conveniently ignoring "what" is covered up).
Notice that the US and other countries involved in the SAR (with the exception of China) - or at least the professionals and experts directly involved - have not pressured Malaysia to announce anything. It's reasonable to assume that a lot of the critical data had come from surveillance resources outside Malaysia, given to the country on a need to know basis specifically for the SAR operations. This data and details aren't to be handed out to the public, and end up with "not friendly" countries. This is China's main grouse: it claims Malaysia "is hiding informations." That's true - information that isn't Malaysia's property which the country is trusted not to reveal without owner's permission.
Don't forget nothing from the aircraft is recovered yet. In fact, even the proximity of the plane's last location isn't known. First things first. Joe Six Pack will not be happy about the lack of news but the release of data isn't his call to make. Nor China's. All in good time.