Top-down splitting the Sea of Reeds card, but also with a dash of Moses being exiled way earlier on I guess? Dunno, that's more a mechanical balancing factor.

That's a very strong wrath variant. Exile not just destroy, and you get to save a thing? I'd upcost it by one. And still use it a lot.

Yeah, wow, this is Duneblast level. That was a hideous beating. OK, I guess this requires you to have a creature, so you can't use it on turn 4 as a control deck; but it's backbreaking on turn 7.

Well, duneblast gives you one extra combat with just your creature. But this is close.

Yeah, it's certainly more powerful than a plain Day of Judgment, but I figured that the cost restriction prevented the decks that we have the most concerns about having good board wipes from running it. Wizards is strongly against the turn 4 wipe, but the heavy control deck that wants that can't cast this turn 4. Also, I didn't think Duneblast was considered playable outside limited and commander.

Oh, the heavy blue/white control decks won't be able to use it effectively. But in traditional mono-white control, this is pretty bonkers. Signet on round 2, followed by a 4-cost angel on round 3, and Plague Wind on round 4.

You can't even kill the 'angel' in response. As soon as you put Swallowed by the Sea on the stack, you've paid the cost of exiling the creature. Granted you can kill the creature when it comes back out... once you've left your mana open for a turn instead of casting permanents, and your opponent's land is untapped, with a potential Shelter in hand.