Yeah, It will probably be Windows XP as the OS system and the processor probably intel core 2 duo or higher
It will be this I reckon, because if they can have a good scalable engine then the more buyers they have not to mention the fact that if it is graphically good at the high end then it can live on as a decent benchmark strategy game that people come back to try after buying a new PC (hopefully the game lives for a year or so).
EDIT: I have had my current PC for nearly a year now and Battlefield 3 which was just released is the first game to even test my hardware, now I cant run it entirely in Ultra but most of it. Now I kind of HOPE that WGEE cant be run by me fully maxed out because it means that its advancing to use higher end hardware.
I ramble too much sorry.