I never used the Sony w/o an external scaler (I bought the VP50 for my previous display), so I can't comment.
Anthem has stated no plans (yet) to upgrade D2 to HDMI 1.3, though I suspect eventually they will. If so, it will have to be a hardware board so either expect to ship back to Anthem or have your local rep replace.
HOWEVER, I agree w/ Anthem so far on whether having HDMI 1.3 is really critical in my pre-amp (read their site for more details).
For instance I still can listen to Dolby Digital Plus and TrueHD since the PS3 (my Blu-ray player) does decoding of these formats into PCM lossless which is sent over HDMI 1.1 to my Anthem. The PS3 still doesn't decode DTS HD MA (there are rumors of a Sony patch to add this for months, but it has not yet been released), but I'm fine with that for now. The only other thing that I think I am missing out on is some of the video color correction signals in 1.3 (deep color, etc). In the end, not having HDMI 1.3 didn't stop me from buying the Anthem D2.
Another option is to find someone or dealer locally w/ a recent DVDO model and borrow it one night for a test and see how the video improves. It would probably be extremely hard to find a D2 someone would loan