Skoll Shorties

Well tbf, those elemental lords are stuck in their plane and cant really boss around the ones left on Azeroth. Even if they could, island expeditions say all the elemental planes are in civil wars with lesser lords. All Thrall needed was for the game to acknowledge that the

Shaman has to convince the fickle elements to aid him.

I honestly think that's what the implication actually is but Metzen didn't want his last Thrall moment to be about him being a failure.

To be fair, Thrall is a beloved self insert that people like and adore. While Nathanos is less of that, though there will always be fans of characters that not so many like. There's a reason people cheered at Blizzcon with Metzen's question. People like Thrall.