I don't think we can necessarily talk about a lack of creativity, but there is certainly a lack of willingness to try something unconventional these days as games today are about as immersive as we can realistically expect them to be, maybe short a feature or two. In principle, there isn't much more to be improved upon. Lets, for instance take FPS. From the horizontally fixed camera of wulfenstein or doom, to the introduction of the free look of quake and the likes. Move over to see the modern shooters that implement the vertial element in terms of aviation, which, while it has been done before, just recently became standard. Most things to be improved upon in this genre is purely cosmetic, and won't make for massive improvements, in terms of gameplay.
While MMO's are a different genre that revolves less about realism, but more fantasy and fancy features, we are also at a point where things are a bit stale. I mean, every mmo has some variation of the healer, the dps and the tank class. While changes here are not only cosmetic, the ground rules for a successful modern mmo have been established long ago with EQ and DAoC. What else is there to add? Prettier dragons? More complex fights? Niether of them will cause any groundbreaking alterations.
I'm actually a bit concerned for gaming as it is.. It's been a while since we saw something new and fantastic, apart from the Wii and Xbox thingy.. but they are mostly for family fun and petting virtual animals/playing tennis.