In that case I think I would prefer a Sony sensor in the short term but I think it is better for Canon to develop their own sensor in the long term...If all we get is resolution I´m out. If we get (significant) improvements in noise and DR, I´m in. I have seen enough (condescending) proof from my Nikon 810 buddy (with Otus 55/1.4) to accept that Canon has a significant challenge.
If it turns out to be FF 7DII type sensor performance, I´ll be very disappointed and probably go for the Pentax 645z. If so, I´ll sell off a majority of my EF lenses and limited Canon to action, birds and wildlife.
I suspect we are seeing 50MP, because Canon might not be able to compete on the lower ISO DR quality front. They are over-compensating for other inadequacies.
If this thing is 16bit with massive DR, then the market will probably justify spending the money on it. Otherwise, it bodes very poorly for the near future of Canon tech, in terms of market perception.
I would only buy one of these cameras if the price was down to $3000 or less.