I personally think Kaeshi Bana stacking is bad as it would mess with the rotation, but my brother had an idea I feel might work for it because it does need to be relevant as a skill.

He suggested making it spread Higanbana as an AOE, so if you're in big pull situations where stuff will be alive for a bit, using that would be optimal over Kaeshi Goken. Seemed like a reasonable way to make the move have value.