It's already finished, and the DLC packs will come out Summer 2017 and Winter 2017 not right at launch, it adds more playable content which people who've primarily beat most of the game can enjoy and make use of.

Only mistake they made was releasing hard mode as a DLC, whether this applies to the overall game or the Trials it should have just been the default difficulty of it.

The price for the pass is only $20 it's not bad at all, and hopefully this mean we will see regular DLC added to keep bringing us new content to play.

I think what separates this from most Zelda games is when you complete the game/story line there is still things to do and reasons for you to play, most Zelda games you beat the final boss and finish the game but not this one.