I think that Canon are renewing their lens range from the most obsure first then to the more popular last. So expect the 100-400II L in a few years. Last year, Canon renewed their 14mm L, not exactly a high volume unit. The year before was the 85L warm over.
So far this year, we have the new 200mm f2 L, the new 800m f5.6 L, this new 24 II L and a EF-s 18-200 IS. That's Canon's 4 lenses per year roll out.
It's interesting that Canon have chosen the 14L first, then the 24L to overhaul. That would indicate that the 35L is next on their list. I doubt if they will touch the 85L again, but the 135L could do with weather sealing. I also wonder if Canon have thought about a 100mm f1.4 L, it's certainly do-able with a 72mm filter thread and it would bridge their
f1.4 lens gap. The 135L's f2 is quite a jump with nothing in the f1.4/f1.2 range above the 85L