Not really much new there. I think most of us who purchased DX10 capable hardware did so because it is much more powerful than any of the DX9 stuff, not because we were all expecting to play DX10 games like crazy right away.
Interesting about Fallout 3 though, as I was quite sure Oblivion had gotten close to maxing out DX9 as they said.
I have friend who is working on a DX10 game... can't say much more than that about his situation.
What he said about DX9 vs. DX10 is that they are different paradigm's of thought about how various Cg elements are handled and processed... as such, it is going to take a while for content dev's to learn the DX10 Tao. You can't take a DX9 path and just massage it for DX10... there will performance hits without much added "wow".
If you start with a DX10 mindset and refactor for DX9 and cut where necessary, you'll get a much better DX10 experience and a DX9 experience that is still fantastic for DX9 standards.
That is about as much as I understood.
Companies that make DX10 capable engines (Epic, Crytek, et al) and game dev's who have designed for DX10 from the get-go will be the first to show us what DX10 can really do.
If you look at the DX9/DX10 screen comparisons for Conan, for instance, you can see significant "advancements" in the DX10 screens wrt the DX9 screens. From what I have read around, the DX9 and DX10 settings for the screens where chosen to give more or less equivalent framerates.