They should just ditch all boss materials and use one single universal material (bring back Stygian Stones?) for all bosses. Bosses also shouldn’t just be boring 1-shots on T4. They should actually provide somewhat of a challenge (and more bosses added with increased mechanics & challenge for geared endgame characters) and give suitable cool rewards.
Everyone keeps saying the game lacks endgame. The current severe lack of challenge and easily obtained items will forever be a problem.