I was talking about the 70mm wide end - it's probably there to go along with Canon's new 24-70 lenses and to phase out the 24-105, but the 70-100 range will come at a cost and it's doubtful how many people will need this part on a tele lens... if you want flexible get a 70-300L as this is much more portable.
There are many times with my 70-200 when I find that 70mm is just barely wide enough for me not to have to change lenses. The wide end of my 100-400 requires me to pop on the 40/2.8 more than a 70-400 would.
+1. I am still rediscovering focal lengths and field of view with my recent shift to FF, and I just shot a group photo with 12 people, spaced nicely apart at 70mm. That 30mm will allow a lot of flexibility, IMO.