In fact, the difference between 8mm and 10mm is quite noticeable, and although I would also like a 8mm F2.8, it seems that Canon does not plan to primes EF-S lenses. Also I think 16-55mm is a useful improvement over the current 17-55. My wish is that it would be 17-70mm F4, not F3.5-5.6 as the current 15-85. What we have seen is Tamrom Sigma and investing more in developing new lenses for APS-C, Canon while showing little interest in the area.
Tell me which EF-S lenses you would like to buy if it existed. Would have some advantage over existing lenses, even if it is just the price.Canon already has the 10-22, so don't need the 6-16.
My short list:
EF-S 8-16mm F4-5.6 $ 800 (non-fisheye)
EF-S 16-55mm F2.8 IS $ 900 (I have a dream ...)
EF-S 17-70mm F4 IS $ 500 (not impossible)
EF-S 55-150mm F2.8 IS $ 1100 (so sexy)
EF-S 135-500mm F4-5.6 IS $ 1200 (not too heavy)
Does my dreams will be met? What is your dream lens EF-S?
Canon already has the 17-55, so don't need the 16-55.
Canon already has the 15-85, so don't need the 17-70.
A 55-200 F2.8 could be interesting.
The 135-500 would be my pick.
Down the road canon may get to some of these lenses you mention, or other variants with similar stats. But, looking at the releases - I think they are going top down. Lots of "L" updates. Which makes sense in a way. as was said by others..,.EF glass works with crop bodies, but the same doesn't go the other way.
If you look at it from the marketing logic standpoint, canon wants People to progress up the line, from a P&S to a rebel, to a XXD, then make the leap to Full Frame. Less people will make the leap if they produce too much good EF-S glass. Like this one you bring up -- "My wish is that it would be 17-70mm F4
, not F3.5-5.6 as the current 15-85." the current one is $700 --- if you make it a constant f4 then that price will jump. If people are shelling out over $1000 on EF-s Lenses, then that would create a very effective roadblock in getting to FF bodies. Keeping the EF-S specific lenses to a minimum makes those looking to buy good glass buy EF lenses (maybe even L lenses) so they don't get stuck in the trap of "now I want to step up to FF but I would have no glass for it."
and finally, your ultra wide ---isn't the Canon EF 8-15mm f/4L Fisheye USM Ultra-Wide Zoom Lens covering that?