I know Bungie has said they are working on adding more to Prismatic in the future. However, in the meantime, Pismatic Transcendence Grenades should not be strictly limited to specific classes. This limitation often forces players who use prismatic into specific pre-ordained build choices in order to maximize their build synergy. If they choose otherwise, they're left with an ability that is completely isolated from the rest of their build. It creates this uncomfortable min-maxing dilemma that isn't easily resolved by those who create and popularize these builds. Meanwhile, all other standard grenades have been changed to be available to all classes without restriction. Therefore, it wouldn't be a massive stretch to do the same for transcendence grenades while new Prismatic content is being worked on. This change would be an overall positive for Prismatic as a whole and open up new possibilities for builds across all classes.