These days I rarely use my IS at all (well once this year) on any of my IS lenses.
Whilst I fancy the 16-35 F4 very much I struggle to think of a use for the IS for my photography, I don't use it on my Canon 800 F5.6 L IS even when hand holding so on a 16-35?
Still if people want it then Canon would be silly not to include it!
I find this very odd. Canon is not likely to drop the price anyways, and its always a net benefit. Always. Im confused anytime someone would 'complain' about it...just doesn't make sense to me. (Sounds kind of photog snobby)
PS- no IS on 800mm....sir i think you are really a statue
My problem/concern with IS is the "dead" piece of glass in the optical path and the fact that IS slows down AF, it can upset tracking as well.
Now I am not worried about AF speed on a 16-35 but I can't help feeling that this lens might not have been a tad better (IQ wise) without it. I could well be wrong but these are just my thoughts. I agree though - Canon will NOT drop the price - it is just not in their vocabulary! Whatever the 16-35 F4 is a cracking lens and I want one!
As to the "Statue" point - no I am not. I am a 56 year old, arthritic, unfit, overweight, smoker, drinker, diabetic and lazy slob! So if I can hand hold the Canon 800mm at 1/500 without IS (almost) anybody can! It does take a little practice though.