I have it on good authority that the Orc Cave is being changed next. The orcs there will be killed off and in their place will be a tribe of sentient mushroom people that come in several varieties from Myconid Worker to Myconid Spore Mage. And at the very bottom will be a boss encounter with the Myconid Queen.
There will be lots of new items that include a new hat (with new artwork) which is basically a wearable mushroom cap, and a Myconid Spore Staff that has charges and a unique poisony AoE spell. There will be a host of new little mushrooms you can find that can be used to make some new potions (including a hallucinogenic one that makes your screen go all weird colours and such), and some new chef recipes like mushroom pie, mushroom pizza, and so on.
There will be a truffle hunting quest added but before you can complete it, you need a truffle hunting pig or dog which a tamer has to train up from a normal dog. Truffles will come in a variety of types, some common, some rare. Some of these will also be ingredients in other things. The rare valorite-infused truffle will be the only way to imbue the myconid slayer property for instance.
And finally there will be some love for gardeners who will now be able to grow and farm mushrooms. One of the rare drops from the Myconid Queen will be a special spore/mycelium which you can plant and it will eventually grow to be a little loyal myconid pet.
It's going to be awesome.