Keep the voidwatch system the same. add point system to legion. have the rewards from legion be old voidwatch gear and plates as a reward for points, as well as new legion gear for points. Even if new legion gear is better, maybe you wanted a piece from voidwatch for something specific. This way, you wont be stuck doing it more. after hundreds of voidwatches, anyone will get tired of it if they cant get their drop because ofthe effort. This way, you can do somethign new ( legion) and work on other stuff that you wanted from VW over time.

if you add points to voidwatch, guess what is next? more voidwatch