Does this mean no 16-35 f/2.8 III?
Impossible to predict. It's a favorite photo journalism lens, probably much more practical than the 12-24 range. And future high ISO improvements may make an update to the f/2.8 even less relevant.
Long term, I would think:
1. 12-24 (or 14-24) f/2.8L
2. 16-35 f/4L IS (the 17-40 f/4L is a goner I think)
3. 16-35 f/2.8L III (I tend to think there'll be an update)
I think there's room for all three zooms, and if push came to shove I would probably favor an optically excellent 16-35 2.8L III over an optically excellent 16-35 f/4L IS. But I'd prefer an optically excellent 16-35 f/4L IS over the less-than-excellent 16-35 f/2.8L II (which I currently own, and love). The 14 f/2.8L II may not see another update.