Dragon Age Inquisition was announced originally to be released on October 7th. Now due to a need for added improvements the game has been pushed by a few weeks to November 21st, as stated by executive producer Mark Darrah.1
Once the game actually gets to you it will be available on quite a lot of gaming options: PlayStation 3/4, Xbox 360/One, and PC.2
There are quite a few games that were going to be released on the 7th of October: NBA 2K15, Alien: Isolation, Middle-earth: Shadow of Mordor, and Driveclub.3 Basically a list of games from all sorts of genres so there is probably something for everyone being released that day. Even without Dragon Age, the wait by no means makes it a worse game. Unless we look at Watch Dogs... but delays usually mean a game will be improved. Let's hope for the best.
Sources: Joystiq  , Polygon