Its not that the deck is inherently flawed
Rapid Strike Urshifu V (Alternate Full Art) $44 8
This allows you to constantly blink Kefka, so you can keep taking advantage of its enter the battlefield effect
By the time you reach ascension a 2/2, doublestriking or otherwise, is going to be super low impact unless you also happen to have some equipment to put on it
With Enies Lobby banned, Rob Lucci players might struggle to put Characters in range for their removal cards consistently This gives Doffy players a chance to keep some of their field intact, allowing for more attacks that eventually win the game
In other words, Achilles will come down for its reduced cost often, provide a decent threat, and buff your entire board as long as he remains on the battlefield