I personally feel like Zoro's relationship with his swords should be deeper than the attractive of a "Kaido slayer". For it to be more believable, he should have been confronted on Shusui being a treasure by people he cared more about, or at least in a more personal way (an intimate dialogue with Kin'emon, for example, to truly empathize with him), and we should have had a scene of Zoro visiting Ryuma's grave before accepting to give his sword back and not the other way around (as it happened). It all felt cheap and way too cold for a sword that was entrusted by Ryuma himself, albeit as a corpse, and Zoro focusing on Enma's strength seemed a bit... puerile, I'd say?