If you never heard the HD650 then I doubt many will complain. The lack of warmth and smoothess is easily apparent though. I'd call them in between so pretty much neutral, more reference sounding than before.
There maybe some normals still lingering in warehouses but I've order three to see if it was just my pair but it seems they all have this change. I hooked them up to my tube amp with very warm mullard tubes, the warmth is usually sufficating but they still have that slightly edgie tonality at times. Compared to my HE-500 they sounded even more grainy.
I've heard the TH500RP is like the HD650 in a different body so I'd love to try those.