Anyone who speaks ill on this lens extending should probably throw out their 24-70s. it's really not that big of a difference, and this makes the 70-200 no different to carry than a 24-70. It's long overdue that someone made this lens more compact, and I'm happy to see Canon jumped on this.
Really changes the game on the logistics of carrying a 70-200--if you have a Think Tank roller, the lens will now fit vertically like the 24-70 instead of horizontally, where it normally takes up the space of 3 lenses. Same thing goes for the beltpacks--it will be infinitely easier to fit a small lens like this into a belt pack and etc.
I'll be more interested to see if this lens got the engineering plastic treatment to save weight, or if it's still magnesium alloy like the EF version. Again, not a problem to me either way as this is how the 24-70 is built and that lens has never caused a problem whether it's been through heavy smoke from a house fire, sand flying in the wind, or torrential rain.