I agree Sony so far is the one showing more of what maybe possible, while for the most part Nikon gains the useful byproduct of their "testing".
Canon I think is doing something interesting by going with sensors larger than 35mm, although this is a bit of a rumor, so not sure if that will be soon or later? I thought by now they would answer to the D800. But these are all incremental closed platform "business as usual" approaches. Ricoh had an interesting appraoch with the interchangable cartridge style, but overall it is limited when you comapre it with other top DSLRs. A7R looks like a great start of something bigger. I hope the innovation trend snowballs.
Everyone is playing it incrementally safe. I wish Sigma would get off their rears and do something drastic with that Foveon chip, license it out to someone with lots of resources to push that chip as far as it can go. It requires no AA filter, no moire issues, more pure color without guessing, and all its doing is sitting in a limited body. Too bad.