Hearthpwn

 next expansion brings rotation, and we will lose roughly 1/3rd of the cards in standard...new standard in april will be:

Ungoro, Frozen Throne, Kobolds and Q1 expansion 2018 only.

edit: point being it might get stale faster as the best decks will likely be found quicker and will all include the power neutrals: Bonemare, creeper, scalebane, etc.