Seeing as how Sigma already released a killer 50/1.4 at an extremely competitive price, I don't see how Canon could compete given that their latest offerings show that all they really care about are slow-aperture IS zooms at exorbitant prices. The idea that Canon will release something faster than f/2, patent filings notwithstanding, is not exactly something I have a lot of confidence in.
Canon simply does not care about high-quality fast-aperture primes for photographers. These days, it is all about cinema lenses and cheap consumer-level zooms they can crank out. Everyone keeps holding on...crossing fingers, hopeful that next year will be the "year of the lens." Again, just LOOK at what Sigma made. They have nowhere near the kind of optical expertise or production capability that Canon has, and they made an AF 50mm f/1.4 lens with corner sharpness that is closer to a $3500 manual-focus Zeiss than it is to ANY other such design on the market today. And then they priced it under $1000. I have no particular love for Sigma, mind you (their QC and customer service leave much to be desired). But this is just embarrassing.
Canon used to be a company that pushed the frontiers of optical design. They pioneered many lens technologies that we take for granted today, such as USM AF; fluorite elements; diffractive optics; image stabilization; all-electronic lens-body communication in the EF mount; and ultra-fast apertures of f/1.0 and f/1.2 that still have no equal today. I find it maddening that this is the same company that now seems to cr*p out a new EF-S 18-135mm cheapo zoom every six months, or produces some insane $35k cinema lens that only movie studios will buy, and leaves everyone else in the cold because we aren't their bread and butter.
The Sigma 50A came out this year. It will take years for Canon to respond with something in kind unless they knew Zeiss and Sigma were playing with retrofocus designs years ago.
The 16-35 f/4 IS is a great lens and addresses a lot of concerns that people had in Canon's ability to design sharp ultrawide zooms. The new 10-18 was a surprise that many were not expecting, and the ef-m 55-200 shows that Canon has not abandoned that platform. The 24-70II sets the benchmark that the fast L primes will have to beat, and that IQ bar is high. And like or not, Canon's releases of the 24, 28 and 35 IS lenses has shown that Canon's days of producing non-L primes without IS is over.
I'm hoping the 50 IS will be a small compact f/1.4 gaussian design that slots between the existing f/1.4 and Sigma's 50A, and I'm hoping that the 50L II will be a retrofocus design that competes against the 50A and the Otus. Releasing the 100-400L II this year will make it look a lot better than what has been released to date, and anything else will be gravy. I'm looking forward to the 35L II and the 100-400 II too, but I'm in no rush. Plus my wallet can't handle it all at once anyway...