My money is on early 2015 (literally, I am saving for the big upgrade as I have 3 EFS lenses to replace).
We should do a poll :-) ... Imho Canon cannot do a 5d3->5d4 (sensor) update which would outperform the 1dx, and I don't see a 1dx2 in 2015.
At the same time unless Canon gets under severe market pressure imho the now collected gimmicks (wifi, gps, touchscreen, dual af sensor for (amateur) video) don't warrant an update a la Nikon d600->d610 yet... the 5d3 is a competent stills camera and a terrific video camera with Magic Lantern raw video, so why rock the boat?
My money is on early 2015 (literally, I am saving for the big upgrade as I have 3 EFS lenses to replace).Incidentally there was a rumour on this site last year that there would not be a 7D2 but a higher specced replacement for the 60D - hasn't that come true??
This rumor was about that there wouldn't be a 7d2 _at_all_ but Canon would re-merge 60d+7d1 into a 50d-like update ... which isn't what happened.