I think it is a great way for Canon to segment it's full frame offerings. It is distinct that the 1.6x fov group is a separate segment of users that Canon would love to keep (until the approach to keep only full frame becomes reality). This group are probably enthusiasts and hobbyists who just want to take pictures with dSLR and are less concern with whether it is full frame or not. They are unlikely to really make technical comparisons from time to time and run after the fastest and lasted high fps, megapixels, or even how many storage card slots are there. In short, they simply love to shoot and care less about the things that will make them stand out as a best in class photographer or gears fanatic.
Coming back to the 6d. This is one good way for Canon to address the need of photographers who are serious about photography and wants to pick up a basic camera that can get the work done. This class might be users from the EOS xxD or xxxD or even film users (film users are full frame anyway). Bing less concern about technical specs and only wanting to get the right picture, they are less willing to spend on higher end models such as the 5d mark 3 or even the 1Dx. If you look at it, the 6D fits the bill - no frills, no complexity - just shoot with the correct setting.
Canon just launched its 5d Mark 3 and there is no reason they will cannibalize the sales of this black horse. It is a great camera and get the job done even if the conditions are harsh and difficult (though not totally fail safe). The company also want people who are fussy about specifications to fit into this 5d mark 3 segment instead of 6D coz they are less likely to head towards the 1Dx (except for those with deep pockets). Seriously, the 5D mark 3 is a great breakthrough if you have used the previous models before. I sort of love it and use it for adhoc assignments. So far, the camera has not fail me. It goes well as a sidekick to my 1Ds Mark 3 and interchangeably when I need to shoot with 2 bodies.
As for 1Dx, let us just say this is really the top segment. You want the best from Canon, you know where to get. No need to look further but make sure you have the dough to get this model.
The introduction of 6D makes the Canon roadmap more interesting. With 3 classes of users, the company can now play around with different technology development to test how to move features into different class of users seeking different desires. Afterall, it is all about user experience marketing for a company that constantly seek to "delighting you always".
