I personally don't think it needs to be changed, but if they do a practice version then a better option would just be to allow starting the fight at the transition points in the fight. This would let your group practice each phase in chunks without needing to start from the beginning. No rewards, obviously. That said, there's definitely something to be said for having to repeat earlier phases in order to reach later phases to practice them since it provides additional practice at those earlier phases making it easier to get to the later phases over time.