WOW is possible, but very unlikely to be done in Gamestudio. For that, you will probobly want (at minimum) the Unreal Engine 2 ($8000 USD). Battlefield 2 could be done in Gamestudio, but the graphics wouldn't be as good. I am currently making a BF2 like game.
For any of that, though, you need to be damned good at scripting.
The Galvanic Productions Hompage:
www.GalvanicProductions.tk
For our current project, click on the Nirvana link.