I think this is a decent idea, I really do, and I really hope Bungie is considering giving all classes a form of transcendence. However, there's some minor functional issues requiring the different damage types to get elemental transcendence. Mainly the most people match their weapon elements to their builds because their weapons directly benefit from the various boosts that they get from their fragments. For example, volatile rounds are granted by various void builds. There wouldn't be any sense in using a solar or arc weapon for a volatile round build because volatile rounds only apply to void weapons. With how ability spam based a lot of builds are nowadays, I would simply rest on letting the Transcendence meter be filled up solely by weapon kills with the matching element type, and Kinetic can count towards everything. It would give kinetic weapons a nice, shiny new niche that would give them a definite edge.