I don't love the idea of mixing a potential Goblin and Rootlands patch (unless we were to get both Rootlands and Undermine as zones), but the questline at Opportunity Point lays some ground work for the intermingling of the themes.
It's quite literally Goblins taking over an Earthen depot, using the hot springs as a "resort", having you disperse an uprooted mole community, then kill a deepstrider who's ghost haunts them, forcing you to rid of it's skull, where it revives after entangling you with roots. I mean, the questline ends with the main goblin at the resort saying "Huh, I guess that makes me appreciate the beauty in nature!".