There is a lot of AI and physics improvement in Cryengine 3. I bet Cryengine 3 Is capably of outdoing Cryengine 2 in graphics quality, but alas they had to lower the graphics quality for the consoles. Don't worry, if the graphics aren't spectacular, there will be a mod out that makes them spectacular.
PS: There are probably only three graphics options because its just a beta, but that might be the way they are keeping it. (I hope not)