1) A minor issue is that there is no such thing as a "perfect" UWA zoom; ... So they won't be in a hurry to introduce yet another UWA zoom that comes up short…as it invariably will be given the high expectations.
I'm not expecting an EF 14-24mm to be perfect, but rather about as good as the Nikkor 14-24mm.
2) Second problem is Canon's current line up on the WA and UWA end and its marketing strategy. The existence of a patent does not mean a product will be forthcoming soon. They introduced relatively in quick succession (not including the 17 TSE, and the 17-40L), the 16-35 II, and 14L II, and 24L II...and note all these are version II “updates”! A high quality 14-24 zoom that goes across all these will be an issue. Especially with the 17-40 and relatively young 16-35II already in the lineup.
I agree a patent does not mean a product will be introduced, but I do think it indicates Canon is considering introducing one.
The 17-40mm is part of the cheap[er?] f/4 line, and I don't think it would compete with a new 14-24mm. The 24mm f/1.4 is two stops faster, and therefore has it's own niche.
IMHO, a 14-24mm wouldn't compete with the 16-35mm as there's a big difference between 24mm and 35mm. E.g. I see a wedding photographer using a 16-35mm, but not a 14-24mm.
3) And above all, the worst assumption is that Canon will "have" to somehow match and compete with Nikon lenses on the EF mount! ...
Once you are in the lens kennel tied to the EF mount with multiple lenses in your collection, you are like fish in a barrel for Canon. And let’s face it, for a high priced UWA zoom, we are talking well-heeled folks who are unlikely to be newbies to the Canon Brand.
There already are used Nikon D700 & Nikkor 14-24mm f/2.8 on sale, plenty good for A4-A3 prints. I'll be happy to settle for that. Canon would not lose sale on a 14-24mm it wouldn't make, but the next time I buy a lens I would consider buying it Nikkor for the D700 - and that's a sale Canon might lose.
Why didn't I buy those yet? Cause I can wait for that saving account to be release in October.