Jade as a mechanic is going to be left in Gadgetzan, I don't see a reason why they'd expand it outside of that expansion.
That being said, it *is* interesting to see that Druid has only two cards revealed so far (Living Mana and Verdant Longneck), the least of all the classes so far. Therefore, at this point, it's hard to say what archetype a majority of Druid's cards are going to be based around, especially since we haven't seen their quest yet.
Either way, Jade Druid will no doubt continue to fight it out into fatigue on ladder with or without significant new cards for a while now. I don't see any Un'Goro cards really changing that, even if they do introduce or bring back some other archetypes of Druid.