Like Diadem, the various objectif is the thing they should do to spice up and change every run.... Killing trash isn't fun in the long run...

I'm sure that diadem could be good without changing much of it, just focus the concept around the objectives and you have less braindead trash killing until Rank V or S pops. Like, give 8 different objectif, every 5 objectif, you earn some eso/lore, you progress into the spawn of rank V and S (and only this way) and reset all 8 objectif (so you can still ignore some that you can't or don't want to do, gathering objectif) Add some rare objectif to spawn a rank V and S when you have done enough (like treasure map ?), rince and repeat.
This way, you have to actually explore the island to find the specific mobs to kill, cristals to find etc, and burning dinosaure island endlessly becomes useless.