he looks too skinny, in SC2 at least he was a pretty beefy dude. his arms dont look strong enough to carry the soul blade on your model, where as in the games he looks like he can throw a bus >_>.
i cant say for sure if it was the same in the first soul calibur though. he may have been skinny there, in soul blade however it was just a recolor of seigfrieds armor outfit.
a little offtopic but related to the character
i hate how nightmare is still in the next soul calibur game, in soul blade seigfried beat cervantes and acquired the soul edge, he was taken over by the sword and more or less reigned supreme until soul calibur 2, when in his ending he finally broke free of the sword and returned back to human form. he truly is the central character in the series butit just seems like they ignored him this time around >_>.
when i saw his ending i was psyched the he was going back to his human form and i was going to get to see the REAL seigfried make his return, as he was always my favourite character. but damnit all ill get now is probabaly just a costume change if i want to play as him >_<, the soul edge needs to change hands, hes had it the last 3 games, cmon namco let someone else have a shot >_<
i would also like to see rock make an offical return, and just toss out astaroth. but thats a completely different character so i wont get into it