Ah I know what you mean now, and yeah I agree.
dx10 is actually doing quite a lot that you can plainly see without resorting to looking in. however, its still not going to be vastly different to the dx9 version of the game. how a game looks is more down to quality of textures, time put into drawing characters and so on. i mean, hellgate looks like utter crap because they simply can't get a complex texture system working with their stupid random map generator, and because that took so long to make(with lots of bugs in the final part of the beta still) they spent time on that rather than drawning things to a better level of detail.
textures and colouring, the basics have the biggest impact. hellgate with the best lighting in the world of everything turned down doesn't look that different because the thing you see the most, all the buildings and characters, all look like crap on the highest setting. put good lighting on a crap texture, its still a crap texture.
the little things though, in world in conflict theres quite a lot of differences, better detail on houses, detail drawn much further in to the distance. there were shadows on helicopters like under the "wing" of the helicopter, all of which was absent in dx9. the craters were better with a wider area of effect aswell, but a lot of that is down to a little extra overhead and a few not "better effects" but easier to use optimisations to add more stuff in.
but dx10 does improve smoke a lot, and other clipping issues. in bioshock and lots of games already you can see things like clouds of smoke clipping heavily with surfaces in games under dx9, but looking far better and much more realistic on dx10. but in the end, its only the edge of a bit of smoke you spin past for a split second.
it gives a little more realism, but makes it in general easier for designers to just do that little bit more. textures, and time spent designing and drawing better walls, characters and stuff are still far and away the biggest things that impact the overall image quality. but those things aren't dx9 either, thats just basic design.