It is Yoshiyuki Sadamoto. Lineart form of the PS2 coverart is included in the second volume of the magazine, with text in the upper-right corner that clearly shows he illustrated the art.
I see... I'm just too used to his NGE, Nadia, and previous .hack// character designs, the style just looked different to me, sorry for wasting your time.
Yoshiyuki Sadamoto isn't a unit of measurement. His style is changing. Also I think he's waaay at the top of the art tier of the project, with variations being made by the artist below him. But all in all I think this looks a lot like his newer stuff (ie Diebuster and FLCL). That's what popped into my mind as soon as I saw the first trailer.