@glupson, First of all, I'll try to control my anger and disappointment at DG for screwing up the sound on such a vast catalogue of wonderful performances from many of the greatest artists, orchestras, and conductors who ever graced the stage.
I usually watch the Vienna New Year's Concerts on PBS. I haven't heard the Karajan performance in its entirety, but there are several positives. It takes place in the Musikverein with its unique and unsurpassed sonics, and it has Karajan (albeit near the end of his life) leading the VPO in which they shared an amazing chemistry. IMO, live recordings from the Vienna "Great Hall" seem to sound a bit better than many of the other venues recorded by DG engineers. The ambience of that concert hall adds so much to the recording.
The audio mix on the live TV broadcast usually sounds pretty good. Live TV broadcasting takes priority over music recording companies, so maybe the DG engineers are not allowed to use their standard over-mic'd recording techniques. Even so, they record and mix their own audio feed for a later release.
I've never heard K2HD, but I own some Japanese SHM-CD's and Blu-spec and since they are simply remasters made from the original digital masters, to my ears they just sound like a cleaner CD with tipped-up highs.