As I already mentioned in earlier posts on that topic, the way a 5DMkII successor turns out(or maybe two
successors, similar to the split of the xxD line into an upgraded 7D and a downgraded 60D?) will be the decisive point for me on whether or not I stick with the Canon system.
Arguably, Canon bodies have long ceased to be innovative, let alone class-leading. Further, more and more former "system seller" lenses (e.g, the f4 zooms, the 100-400) are either starting to have good alternatives from other system manufacturers (although it seems that Nikon's 24-120 f4 is not as good as the 24-105), finally have viable third party alternatives (e.g., picking a Sigma 70-200 f2.8 OS over the 70-200 f4 IS for a comparatively modest premium), or are so desperately in need of an upgrade (100-400) that one is hesitant to shell out the still considerable sums for these methusalems.
And seeing that Canons product releases in recent years are apparently only catering to either the growing crowd of DSLR newbies (with Rebel warmovers usually after less than a year and new EF-S kit and superzooms) or to professionals and rich hobbyists (with their high-end L super teles, niche products like tilt&shift lenses etc.), in the process totally neglecting the "middle ground" for us enthusiasts (and no, the 70-300L doesn't count, as it is IMNSHO way overpriced for what it is), third-party gear is getting more and more attractive. Just consider the recent smattering of new and often excellent lenses by Sigma (8-16, 85 1.4, 120-300 2.8 OS etc.) plus Tamron getting its act together and finally offering a modern AF drive -- since you can get these lenses for other systems as well, why should you stick with Canon?
I still like Canon a lot, regarding their ergonomics, their aesthetics (yes, this is tongue-in-cheek
, but I really
find in particular the Canon lenses to be much more aesthetically pleasing than anything else on the market) and I really like my collection of Canon lenses... but currently there is little coming from Canon to keep me excited.
So please, Canon, get your act together, become a market innovator again, stop overprotecting your priced 1D(s) series by crippling semi-pro/enthusiast products, and when it comes to pricing, don't be as greedy as you were with your recent lens announcements -- after all it's not the rest of the world's fault that Japan is apparently unable to devalue its currency to allow its industry to stay competitive.