Ruin Explorer
Legend
I wouldn't quite say so myself, because both are well-made and distinct settings (Theros being one of WotC's better efforts). You could probably make an interesting mash-up of both but you'd need to sort of roll Theros' history back to the end of the Age of Trax, and make the "heroes" who fought the minotaurs to essentially be colonialist invaders, and group the minotaurs with other races. The nature/civilization conflict works with that to some degree. You'd also need to rework the gods, who in Theros are both less powerful and more embodied. It would be like an AU of Theros where things went very differently from that point.Plays nice with Theros, too.
Finally you'd need to pick whether you went with WotC or OotDL Satyrs and Minotaurs, and how you positioned the other OotDL races in the Theros setting. Additionally, you probably couldn't stack the "Heroic Origins" (or whatever they're called) of OotDL with the Supernatural Gifts of Theros unless you wanted some really strong low-level characters (which might actually be fine), and to fit the adventure/campaign you'd want the Heroic Origins.
Overall it would be a very significant amount of work, more than say, adapting Kingmaker from Golarion to the Forgotten Realms even. Maybe slightly less than adapting a War of the Lance campaign to the FR though.