It's alway something. If a trailer is too fancy and the players who buy the game see that the graphics aren't up to the standard a 2 year old trailer promissed, they're angry (yeah, mr Witcher, you know i'm talking to you) and if a trailer is realistic in terms of what kind of graphics are to be expected, they're also angry.
The graphics are reasonable. Let's just wait to see the finished product to know why those graphics aren't spectacular. The bigger the world, the more content in it, the more you can interact with things in this world, the amount of quests, the amount of spoken lines etc,...this might be why the graphics are reasonable instead of superduper-out-of-this-world-crisp. There is always a reason for things like this. And starting to complain like a little kid who thinks their lollypop isn't quite big enough before he has even purchased it, is kind of useless.
It's always better to get a product that lives up to the advertisemants than a product that is only a shadow of the advertisemants.