I hope the "wide angle f/4L with IS" which "is “definitely comingâ€" would be an upgrade to the 17-40 f/4 L
I don't see a response to the Nikkor 14-24mm having an IS. I don't see much sense in a 16-35mm f/4 with IS, but I don't see sense in the new 70-300 either. The 17-40mm f/4 could use an upgrade, and if the Nikon 16-35 has an IS, why not the Canon 17-40 ?
[Well, I don't see much sense in IS on such a wide lens, but people ask for in, and Canon has to compete with Nikon, so whatever.]