I think we should withhold judgement until we see IQ and noise control from this 20.2 megapixel sensor. Because in the end, isn't that what really matters?
Let's say it's stellar IQ... as good as the 5D3 (it won't be better, Canon's not going to put their best in a 6D and second best in the 5D3). Then so what? It's a great sensor in a hobbled body for $2k... who's buying it?
The price gap is too large to entice an average consumer up from the Rebel line. And the features are not up to spec for working pros. There is no question that it's an entry level FF... but what are the features (other than the sensor) that make this better than a 60D? And if the only benefit over a 60D is the sensor... then how many customers are going to pay that much more for a FF sensor when the vast majority of Rebel customers don't even know the difference.
Guy walks into Best Buy to buy a Canon DSLR. Salesperson shows him a 60D for $900 and a 6D for $2000. Same body and specs but 6D is FF... what's the customer going to buy? Is the salesperson going to be able to explain the benefits of FF... many of the salespeople probably don't even know themselves.
Sure there are many folks on CR reading this right now salivating that they can get a FF camera for $2k.... but nobody on here is an average consumer... we are all camera enthusiasts reading up daily on how great FF is... so the person this is targeted for is a person that is lusting after FF, is unwilling/unable to pay $3500 for a 5D3, and doesn't need the AF and speed of a 7D. How big is that market?
I disagree on your assessment of this body. While I agree many people are underwhelmed by this offering, let's keep in mind that Canon is still in "catch up mode", trying to deal with how it will respond to the D800. This was likely in the pipeline long before some high MP body was conceived, and I think it fits in to the Canon lineup quite nicely.
That said, I think this body has a place in the toolbox for many working pros. I, for one, would much rather have an affordable full-frame back-up body for events/weddings. Don't get me wrong, the 7D has worked as a solid back-up for me thus far, but it has left a lot to be desired in the realm of low-light situations where AF and noise management are critical.
With the ISOs and (most likely) reduced noise over the crop-sensor of the 60D, this will become a go-to back up for budget conscious pros. I think it will be immensely popular with pros, and enthusiasts who are just looking for a little "more."