The amount of origanality you want, you'd probably have to code the game yourself.
If you want to create a game very origanal, your not going to find an editor that lets you do it easily. For one, "EZeditors" are made to make a bulk of different games that run along very simple principles (aka experience, mp, etc.).
My best suggestion would be to download Multiverse (when it goes gold, and yes it will be free) and learn how to mod its code. [google it]
---Info on Multiverse---
Multiverse is one of the few (if not only) fully 3d mmorpg creator.
To completly make your game origanal, you would need to learn some codeing; however, one could create a game using the games prebuilt engine with, perhaps, simple coding knowledge.
Multiverse is free (only if you don't make people pay)
However, Multiverse is currently in open beta, and should only be used right now by those comfortable with buggy errors, console commands, and ini file editing.
