To me, the CG seems more like a monster, where the model... I dunno... looks like Godzilla had sex with the creature from the black lagoon. It is cross eyed and just looks a little silly to me. Now, granted, when I was a kid, it was scary although Medusa was always the thing that freaked me out the most in the original. From just what we have seen in the trailer alone, the CG Kraken seems like the terrifying behemoth from the deep that one would expect, while the old Kraken almost seems like an oversized ugly merman.
Again, CG can be horribly overused, but I don't dislike it as a tool to really emphasize the enormity and grandeur of creatures like the Kraken.
In my mind, looking at the scale of the Kraken from the original movie, it seems defeatable by men... well... enough men. With the new one, it seems so ridiculously huge that the ONLY possible way of defeating it would be through some other means... something magic or supernatural, and isn't that the point of the story, that men cannot beat it, only Medusa's head?