Canon's biggest problem is pretty much the same as Apple's right before Steve came back. Their R&D is spread across too many products that are poorly and inconsistently differentiated, and there's no single product that is clearly and unambiguously the best. The supposedly top-of-the-line 1D series clearly wins in terms of most of the pro body features, but loses to the 5Dmk3 in terms of sensor size (limiting its ultra-wide-angle use). The 5Dmk3, in turn, kills the 6D in autofocus but doesn't compare in low light noise or in end-user features like GPS and Wi-Fi. And so on.
I have no idea about Canon's R&D budget is spread out, but after watching for the last 10 years or so I've come to the conclusion Canon might, just might, have some idea about making mass-market cameras! The don't always have the very best of everything (think sensors at the moment!), and they often don't have the best specifications in their class (for example, as far as I can tell, Nikon's comparable cameras nearly always have "better" numbers - more zones in their metering matrix, etc, etc), but the Canon cameras still turn out to be great photographic tools ... especially in the context of Canon's overall system. Take the 6D. Many people (including me) were underwhelmed by its specs sheet ... but now the 6D seems to have developed a pretty good reputation and be selling well ... and I'm one of its buyers. Certainly it has its limitations, but it's a good camera which can satisfy the needs of a lot of people. And it seems to be doing better at that than many of its competitors, whatever their spec sheets may say.
I also think Canon has very clearly differentiated its cameras - certainly its 35mm sensor ones. The 1Dx seems unambiguously the "best" because of its ability to deal with the widest range of conditions and speed requirements. The 5DIII has a higher resolution sensor, but overall seems a clear step down - by all reports the files aren't as flexible, it's FPS is much slower, by all reports the AF isn't quite as good even though the systems are similar. And of course the 5DIII ergonomics are quite different, particular the smaller body - a positive for some and a negative for others. Anyway, the choice is clear - if you want a smaller/lighter camera than a 1Dx, or more resolution is a critical requirement, the 5DIII is your choice (I'll ignore cost issues for now). And then there's the 6D. If you can live with a more limited AF system for tracking moving subjects and focusing on off-centre targets, and the x-sync speed - or smaller and lighter is critical to you - it will give great images and at a significantly lower cost. And I think the reality for a lot of people is they can live with those limitations because, as much as they might like to have a camera with fancier specs, in practice their photography doesn't really need it. And Canon threw in a few bells and whistles too, such as wifi and GPS, presumably to help attract some of the upgraders - but I doubt there are too many 5DIII who are coveting a 6D just because of wifi and GPS. (I'm sure there are some 5DIII owners who'd be happy to have the features, I'm just saying I struggle to believe the majority of 5DIII owners would rate wifi and GPS as that important, at least in comparison to the advantages the 5DIII over the 6D.)
Oh, and dump the mirrorless line. It was a failed experiment. Or at best, make it electronically identical to the consumer crop body, just in a different case, with the mirror box headers unpopulated, and with slightly different firmware.
The EOS M does seem to have a been a bit disappointing, even if the firmware upgrade helped a bit. I find it interesting Canon hasn't really gone after the mirrorless market, but the question is why haven't they? Is it really as simple as not wanting to cannibalise their DSLR sales, or is there more to it than that? Perhaps Canon thinks mirrorless won't really deliver the promise/hope of a significantly lighter/smaller system (including lenses) unless the sensor size is reduced (like m4/3) but thinks the IQ possibilities of larger sensors are more important to the market it's going after? Perhaps Canon doesn't think mirrorless offers enough genuine benefits over a DSLR (at least mid to high range DSLRs) as a photographic tool, that it's worth it at this point? Will that change in future with advances in technology like EVF, batteries (to drive the EVF!), and AF (and the 70D sensor tech hints Canon could be working on that one, at least)? Perhaps I'm giving Canon too much credit?!
Anyway, I look forward to seeing what the camera landscape looks like in the next year or two - will 35mm mirrorless be taking over, or will be a short term fad which ends up a niche player but fails to push out DSLRs? I've got to say the attraction of the OVF (for many people, I believe) means I'm not convinced DSLRs are going to die out that quickly, but we'll have to see.
Just my $0.02.
With my $0.02, we're up to $0.04 now I guess