The game has been released to an expected critical reception. It's still a repetitive Dynasty Warriors game, but the Zelda veneer makes it palatable.
From TGS 2014, Koei Tecmo has detailed future updates and premium DLC:
There are also four upcoming DLC packs. Here’s what they’ll include:
The “Backdoor” Hyrule Warriors pack: a new weapon, new scenario, an adventure map, and two costumes. Will release on October 16, 2014 for 1,200 yen.
Twilight Princess pack: a new character, a weapon, an adventure map, and two costumes. Will release in late-November for 1,200 yen.
Majora’s Mask pack: two new characters, an adventure map, and three costumes. Will release in January 2015 for 1,200 yen.
Ganon pack: two new game modes. Will release in February 2015 for 500 yen.
Read more at http://www.siliconera.com/2014/09/18/hyrule-warriors-update-makes-games-main-villains-playable/#AHaPHQcUYgGQA0qy.99
Also, the antagonists Cia, Volga, and Wizzro will be playable in a free update.
Combined, the DLC packs total 4100 yen (US$37.73). For reference, the game costs 7,389 yen (US$68.06). Given history of Warriors games being stuffed with content, this DLC offering is quite pricey. Hyrule Warriors looks to be made from scratch (something that Dynasty Warriors or Samurai Warriors don't look like they could say), so there is an argument to be made of how this DLC is possibly not a trivial effort. I'm curious as to how the pricing will work out in the rest of the world.