If Zoro becomes a sky-splitter in his battle vs Mihawk, maybe it'll fit his powerscaling at that time. But thematically and specialty-wise, it will be more or less unfitting imo since the sky-splitters are all the users of CoC Coating which crushes things with that no-touch zone instead of cuts. While both Zoro and Mihawk cut large stuff using top notch AdvCoA instead.
Even without being an AdvCoC sky-splitter, Zoro may become an AdvCoA sea-cutter and iceberg-cutter specialist later in his battle against Mihawk, which is also a better depiction of top swordsmen battle compared to CoC-skysplitter that the Emperors specialize in.
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