I tried it with the Siren first, but the Siren can't pull it off. Not enough defenses to survive without taking a lot longer. Forcefield ftw XD I'd like to be able to kill the mage quickly with this, but it seems like it won't work any quicker than mid game, and I'm not a good enough player yet to figure out how to adjust the deck to plan for that. That's why I'm asking for help.
As for why Whirlpool + Swamp, there's actually more than the obvious reason. Swamp makes it so after they've sent some creatures after me, when I run into the Swamp, everything they've spent that time sending after me (if anything) now has to waste time being slowed before it can do anything, plus they'll be hit by the pillar. that increases how long I'm safe for by a lot. Whirlpool also hits all the creatures at once, whereas other options only hit the mage, not threatening anything else at all. I was also originally thinking that if an enemy mage tried to teleport out, I could simply force pull then force push them back in, but since they'd have their 2 movement, i've realized the trick won't work like I wanted it to.