I think one of the problems with Canon's DSLR lineup is that they have too many models on the market. It is not really economical to support future development of all of them.
I've been saying that for a long time. Ignoring the mirrorless segment for the moment, the right number of DSLR models is 4:
- Consumer crop-body DSLR (based on the 70D)
- Pro crop-body DSLR (7DMk2)
- Consumer full-frame DSLR (6D)
- Pro full-frame DSLR (1D-???)
I could possibly accept 5, but only if it's because they continue to sell one older model of consumer crop-body cameras to hit a price point. Any more models than that, and your products are cannibalizing each other's market share way too badly.
What this means is that they need to merge the 1D and 5D lines and price them where the 5D line is currently. They also need to kill the Rebel line and rebrand the 70D as the Rebel T6i. There really is no good reason to have two consumer crop body lines that are barely differentiated, much less two professional full-frame body lines that each have some features and not others.
Also, the high-end model should always be a strict superset of the low-end model. Having features in the 6D and 70D that the 7D, 5D, and 1D don't have is absurd.
Hmmmm .... I disagree with what you said about 2 FF bodies. The current system is pretty good in my opinion. One low cost, one mid level and one high end. By merging the 1D and 5D I presume the body would be 1D shape? That would annoy a lot of journalists and wedding togs for sure. The 5D range is the bread and butter for a lot of folk. The 6D is targeted for a different kind of photographer. It seems more travel and casual stuff. Maybe first time FF buyers etc. also a one camera does it all top end model would be very pricey. The jump between 6D and 1D is really high.