What, intraframe compression like MJPEG? File sizes for 2k (much less 4k) movies would be enormous. So interframe coding won't be going away. Closed GOPs, as on Blu-Ray, of 24 frames or less are still reasonably seekable. Improved color space would be nice though.
I have to wonder if all this (4k standards, hardware, and especially content) is going anywhere any time soon. We're seeing hardware before the spec is firmed up, while content is severely limited and exclusive to a proprietary Sony server.
DVD replaced VHS relatively quickly, but Blu-ray has not ousted DVD yet. Most folks now have a flat panel. And many members here, who of all people you'd expect to be avid for the next improvements, have expressed the intention to wait and see.