A very believable rumor, Sony has been outinnovating them for a while now and if it's costing them sales they surely aren't going to take it lying down. Digic V with better video is almost certain (I hope they get rid of the moire and increase detail before they try and get any bright ideas about 1080/60p; given the 1Dx's specs I'd say that's probably reasonable to assume). It would be nice to see built-in HDR but Canon seems hell-bent on making you do it by hand (which is sooo five years ago).
I agree on paper Sony may have the upper hand but in practice the A77 is way too noisy compared to the 7D, K-5 or D7000 which are relatively close with each other.
Just look at the RAW there is very visible noise even at 400 ISO