i heard from someone that the system requirements might be higher because there is much more you can do in this game than in FO3. bigger areas. more guns. more characters. more melee weapons. + a melee system i hear. so id think the more they ad to FO NV the more it will ask for in System Requirements. im starting to think i shouldnt have pre-ordered til i read the official specs >_>
All those things have nothing to do with System Requirements outside of one thing - needing more space on your harddrive to install the game to. Those things have no correlation to the computer hardware needed to run the game. Daggerfall had more weapons, NPCs, quests, and a much bigger map area than Oblivion, but it runs on very old PCs.
Polycounts, complexity of shaders, number of textures and their resolutions, number of characters and objects
in one area at one time, and complexity and number of parallel scripts active, are some of the things that determine system requirements.