Very interesting ideas, all of you!
Here are a couple of my wishes:
*Canon EF prime lens 350mm f/4 IS priced at or under $3000. In other words, let's fill the gap between lenses with a 77mm to 82mm front element...and the "supertelephoto" megapriced group, whose front elements are not smaller than 5 inches...
*Canon EF zoom lens 22-120mm, f/3.2, multi-mode IS, no barrel or pincushion distortion anywhere in the zoom range, and very low to no CA. Resolution on par with, or very close to the current 24-70 f/2.8. Price $1899.
*Price no object...Really fast primes or zooms from any manufacturer, that are state of the art optically. Specifically, something at or around 60mm, 90mm, 110mm, and 160mm. I'm taking this fantasy to the extreme, so the 60mm range would be f/0.4, the 90 f/0.7, the 110 f/0.9, and 160 f/1.2. All would have fast autofocus and 4 or 5 stop IS. All would be as sharp over 90% of the image area, as the current series 2 Canon supertelephotos. All would be as light and strong as possible, with adequate weather sealing. And again, all could exist inside one zoom lens...although the price would be far higher than if it were divided into prime lenses at the various focal lengths...Such a zoom would be $15k to $20k in present day dollars...
*Canon replacement or alternative to the 1DX, in two body versions. One a downsized, cheaper version with a lesser AF, the other the full 1 series body. Both would use a future tech sensor achieving edge of the art dynamic range and s/n ratio, with resolution from 19 to 26 MP. The sensor would not be "full frame" at 36mm width, but a crop, about 32 to 33mm in width. Incorporate some innovations from other manufacturers somehow...perhaps by purchasing controlling interest in one or more of those companies.
*Higher viewfinder magnification combined with larger "apparent field of view" via the finder...for all Canon bodies (except maybe the Rebel line). An image through the viewfinder, with a 50mm lens mounted, focused at or near infinity, should show objects exactly the same size as the naked eye sees them...AND NOT SMALLER than the eye sees them.
*Advanced autofocus, as some others have said...with some kind of eye movement detection.
*Leica somehow modifies some of their M-mount lenses to work on DSLR bodies...and makes them fully automatic, electronic, and with IS...haha.
*A CANON 1.7x teleconverter that is optically superior to even the current series 3.