I agree the 100-400L could really benefit from an upgrade, but the rumors have been out there way too long for me to get excited. If Canon finally does announce something, I will be very interested in upgrading if the price is not outrageous.
Until then, I will happily continue using the existing 100-400L. It's probably my 2nd most used lens, and it takes much better photos than a rumor.

I had a less-than-great copy, Or a copy that needed some tweaking, That coupled with the physical length issues lead me to sell it off late last year and get a 70-200 f/4L IS, The 70-200 f/4L IS + 1.4x tcon produces much sharper images, Albeit its not as long as my 100-400 and i really miss that extra 120mm sometimes...
, i can't see Canon wanting a revised 100-400 cannibalizing it's sales.
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