If the C400 ends up being a combo of the C200 & the C300 II, then I'll order it immediately. The C300 II is great but the ergonomics are off (too top heavy and a little too big) and it lacks high frame rates without cropping the sensor. The C200 has the ergonomics and the uncropped frame rates, but lacks the middle codec that makes it broadcast worthy.
I can see the C400 filling this gap. If Canon plays their cards right (which they rarely seem to do), the C400 could be the best EOS Cinema camera ever made and even possibly the best CINEMA camera ever made, period. It could feasibly beat out Arri and Red for many shoots where a small compact cinema camera is needed.
I hope they announce it sooner than later. I am underwhelmed by what I'm seeing from the EVA1 and the only mode worth shooting on the C200 is RAW, which is too much to deal with for most shoots. The FS7 remains the most capable middle ground cinema camera out there, but it's big, awkward and has that weird, Sony color science, which only looks good in certain shooting situations. I thought Canon would take the crown with the C200, but it seems to me they are waiting to do that with the C400. The C200 is a bit of a stop-gap and the C400 will probably be the camera many of us have been waiting for.