Wait, what? You don't think DX11 is a big improvement over DX9? Just the new ways it can deal with lighting alone is worth it.
But one has to understand the mind of the average, no I should say the vast majority, of FSX users, and they want what they see to resemble what they see in real life. That is why there are so many texture add-ons, mesh add ons, why people insist on using the ENB mod even though it makes FSX terribly unstable.
I am telling you, MS will market Flight in two ways, one as a game for those who have nothing to do with FSX or FS9, and then to the already hard core flight simmers, that it is FSX with better graphics and stability. That alone will get most FSXers to get Flight.
It used to be that if you want FSX to run at its peak, you had to use Win XP. Vista and FSX just did not play nice together, and all sorts of things had to be done, like mess around with sound quality, to get it to run fairly stable.
Now that is not at all the case. If you want FSX to run at its peak, you need to use Win 7. FSX on Win 7 is more stable, and runs faster than it ever did on XP, as long as you have entered that HIGHMEMFIX line into your.cfg file.
But you have a full DX10 FSX, or better yet a full DX11 FSX, considering you are dealing with water, clouds, road and building night lighting, DX11 will make a vast improvement over what default FSX looks like.