well, I'm wishing for more megapixels and one or two stops more dynamic range at low iso. I think the 5D III are targeted at wedding/event photographers. As a landscape shooter I find the 5D3 features a real disappointment.
In principal I agree with you. of course, we have to wait and see measured tests (such a dxo) to see if the dynamic range has improved at all. Not to say there are not some useful features in the 5d3 for landscape shooters: bit of better weather sealing, much batter bracketing, and the 6fps can be useful when bracketing shots. In addition, it looks like the horizontal banding when shadows are pushed are improved.
As far as in camera HDR goes, no self respecting landscape photographer would ever use that feature. if you are a landscape photographer, the d800e is currently the holly grail. and in any case, the advances in 5d3 may be worth about a few hundred dollars over 5d2, if you are a landscape photographer. its just not the most cost effective tool for that.