I think a Graal version of the game Advance Wars would be awesome. It's turn based but it's still a whole heck of a lot of fun... Plus you don't have to worry about lag issues. With cool stuff like weather condition and being able to build units and all that stuff... and even an online map editor... I think it would be amazing if it were massively multiplayer.
Of course it would be designed to fit in with a Graal theme... either GK theme or classic theme.