While I have not seen any sort of announcement, it almost seems like Canon is going to bring us a new tier of lenses. Somewhat similar to the EFs 17-55 and EFs 15-85 from years ago. Sub-L but much better than other consumer lenses. Excellent optical quality (based on reviews of the 28-70 f/2.8 and MTFs here).
Personally, I am excited to see if they have more in the pipeline. Just thinking about it, we have at least three zoom lenses in this group, the 16-28 f/2.8, 28-70 f/2.8, and while not a constant aperture lens, many hold the 100-400 in high regard, it seems to fit as well. Those three would make a great kit and cover a lot of ground for people.
Interesting. I like it.