Well even the minimum number in the patent is quite long compared to the original 100-400. So that's why I am talking about a longer physical size even if Canon could make it shorter - this particular patent says 5cm longer which means it isn't in that 70-200 form factor anymore. Don't get me wrong I'm sure it will be bloody good as usual for their refreshes but the "purpose" of the lens changes slightly in that it would take the role of my Sigma 120-300 (for example) which goes in a backpack, not really a "in shoulder bag ready to go travel lens" that I use my 100-400 for.
If you look back at the 70's, SLR equipment has been steadily growing in size. Bigger glass has the potential for better optics, so it's not too strange that this trend continues. Fortunately the materials are getting lighter though.
5D3, 5D2, Sony α6000 | SY14 f/2.8, Ʃ20 f/1.8, 24 f/2.8, 35 f/2, Ʃ35 f/1.4A, 50 f/1.8 I, Ʃ50 f/1.4 EX, 100L Macro, 17-40L, 24-105L, 70-200 f/2.8L IS II, 1.4x II, 70-300L, 100-400L | E-mount: SY12 f/2, Ʃ19 & 30 f/2.8 EX DN, 16-70 ZA OSS, 55-210 OSS, Metabones SB | FT-QL, AE-1P | FD(n) & FL lenses.