Amaterasu is still really useful for Seraphim Lucifer teams, since you can't do Morning Star when you're at 1 HP, so her ability to heal you without using turns helps a lot. That team is not that great for Zeus, though. Since you can't just nuke that dude in a single turn, there's a good chance you'll die--especially if he freezes all your gods and drops your HP to rubbish.
Anyway, a long time ago, someone posted about the "boss suicide" strategy here. Well, I succeeded against Zeus, using Anubis's active skill. Zeus hit himself for 272k with Super Nova and killed himself. Pics coming soon. =)