The Witchwood is a traditional Hearthstone expansion but it seems the pre-order nets you 20 extra packs than it did before. Seems to be an adjustment on Blizzards part as it seems the general community consensus is the game is really expensive to play. Still is, but they seem to be tossing in more value, which is nice.
The Witchwood is also shipping with a new single player game mode similar to Dungeon Run of the last expansion called Monster Hunt. In this mode you play as one of 4 unique heroes where you take on 8 bosses to complete the Monster Hunt. This seems to be a cool extension of the Dungeon Run mode added in Kobolds and Catacombs which was my most played aspect of the last Hearthstone expansion.
I have a special fondness for Hearthstone but the thought of getting back on the daily grind makes me get all queasy. It's a great game and possibly the best free to play game ever made but you either have to sink a ton of time into it daily to get enough gold to open packs or spend more than $150 a year to open enough packs to remain competitive. Both prospects, right now, seem unfortunate to me but i'm really happy the game is continuing on and people seem to love it which is awesome because it's a game that should continue to be improved.
https://playhearthstone.com/en-us/expansions-adventures/the-witchwood