The pics aren't as drastic as I thought, but my opinion on this still remains.
Aquaman shouldn't be nearly as big or strong as Superman. It ruins the perception of his supposed strength. After all, he's always been known as the strongest of all Superhero's alongside the Hulk. Seeing Aquaman this huge will just look weird on camera and make it harder to believe in the idea of a Superman on Earth.
If anything, Eisenberg and Momoa should've had their roles reversed. That would be more believable (comics wise) that what Snyder has done.