Vulpix pretty much hit the nail on the head. 80 Hp means anytime you actually manage to mill a bunch of cards from your opponent's deck, all that energy is going to be lost and then you're back to square one. Gardevoir, as mentioned, is extremely frail, and after they KO Gardevoir you now mill half the cards you would otherwise, as they proceed to continue sweeping the field. This deck would also be running a Stage 2 AND Stage 1's, making it extremely tight space and inconsistent, something that a mill deck cannot function with. There's no room for any disruption cards.
Overall, it just won't be able to set up fast enough. Any attacker in today's format OHKO's Swoobat, and since it's a Stage 1 that requires a ton of energy to mill effectively, it's impossible to get right back to milling immediately after getting KO'd, as it's predecessor Durant could easily do.
Overall, it just won't be able to set up fast enough. Any attacker in today's format OHKO's Swoobat, and since it's a Stage 1 that requires a ton of energy to mill effectively, it's impossible to get right back to milling immediately after getting KO'd, as it's predecessor Durant could easily do.