What's the current issue? Too many people only getting world boxes / world keys.
What's your suggested way of fixing it? Either A) Remove world boxes as a whole. Only drop keys that the player could then bring to soulroom for unique world boss drops or B) Make an way to swap world boxes into keys and vice versas at a 1:1 or 2:1 rate.
How will this benefit player/server? Make it so people are motivated to go to world bosses.
How could this be expanded in future? Add unique rewards to world bosses such as pets/auras unique to that boss. i.e enraged olaf (if it exists) aura could