What made the Kraken picture so great was that the environment played a significant role in the composition. But Tiamat's environment is mere window-dressing, and Lich has none at all.

There's also the matter of a dynamic perspective. Kraken was looking up at the viewer like the evil creature of the deepest deep that he is, whereas I'm more or less eye-to-eye with these guys.

They're good, but not Kraken good.