Corsola is interesting on paper but I just don't think it's worth it other Relicanth or Golem. While it does have Regenerator and Recover, giving it far more longevity than Relicanth, Corsola is slower than the likes of the Probopass and is incredibly passive when compared to Relicanth. I wouldn't say this mon is hard because it does have some good qualities but I can't justify using it much.