I can´t see why an Arri announcement should be the "clearest signal yet" for a C300 update, but otherwise your analysis is very plausible. I was surprised and disappointed that nothing happened last year... I watched "Need for Speed" yesterday just because I wanted to see more C500 footage from big productions. Pretty good, although I have to admit that many of the daylight shots filmed on Alexa looked even better. Personally I feel not really in the mood for Sony yet, especially I doubt that a 7000.- sony camera like the FS7 can have the colour accuracy of a Canon C500 which can almost be had for about the same price used and with Shogun. I´m just not impressed by the test footage on vimeo from the FS7, and the official introduction video did not even have a proper grade (I´m sure they forgot about the delogging). On the other hand I ordered a very early C300 immediately after the first good demos. The battery life of the C300 is just stunning, I´d never ever go back to less, let alone bulky V-mount batteries and the need to lug around generators when going on field trips. So, I´m keeping my fingers crossed for the C300/C500 Mk2. I hope and I´m quite sure Canon will not offer Full Frame models, as NOBODY in the professional field would give a damn. Just use a F2.8 instead of F4.