I don't know. You can make some "terrain" if you like, but this is just for a closer scenery. Also, if you have skills with little imagination you can make a illusion that scene is bigger, and make whatever you want.
FPSC is really great level editor for creating fun games, games for you and your friends (If you are lucky then you might be able to sell some product
), and to tell you the truth I expect more from FPSC only when DirectX 10 will be released. Untill then you must except the fact that graphic engine is not capable enough to render huge amounts of polys.
I work in a game studio as a 3D modeller, and with our own graphic engine we achieved much more better results with high poly models (vertex shader 3, bump and parallax mapping.. etc, etc).. But! This graphic engine was developed in 2 years of hard work and this is not the same as FPSC.
To make myself clear, I see many guys here expecting a Far Cry - Half Life graphics, physics, AI and other nice stuff for a really low price. Those games are produced by proffesional teams, and ofcourse with "decent" budget
. My team have a 24 members for example (programers, modellers, animators, musicians...).
So, if you want to make a "Oblivion" your first step is to learn C++ and DirectX, and then your terrain would be great. As I said above for FPSC you must have imagination, limited by technology, but with FPSC everybody can make games and have fun. The skills for making games are implemented in this tool. When you accept this, then your terrain will be great in your and everybody's eyes.
Also, FPSC is really great for understanding the "making the game" technology. It's great to see some kids here learning to create modells, ai scripts and stuff. Who knows, maybe one day some of them will make great titles like Doom3,Half Life ...
. My advice to you and others is, if you like game development - stay tuned, learn, create and play with FPSC and if you are strong enough to "survive" sleepless nights then you will acchieve something.