Complex sentence: Grievous was to undergo a design change in the seventh season to look more like his design in Revenge of the Sith, though the series was cancelled before this could happen, the unfinished animations of the Crystal Crisis arc showed this design.
Split into simpler sentences: Grievous was to undergo a design change in the seventh season to look more like his design in Revenge of the Sith. Though the series was cancelled before this could happen, the unfinished animations of the Crystal Crisis arc showed this design.