Just an idea how about the queen slime? I know you just want to make better/ condensed stuff but think about it, the king slime is just a helpful mini boss for items and stuff so how about the queen slime its summoning item (the queens crown) has a 2% 3% in expert mode to drop from slimes
The queen slime
The queen slime has lower health but shoots projectiles at the player, in expert mode the queen shoots 3 spikes at a time which do high damage. the queen does not spawn minions
The drops
Instead of the slime gun there will a magic weapon called slime bolt this shoots a slime projectile that Bounces an insane amount but does low damage ideal for caving
Instead of the slime hook there will be the blob of slime this is a weapon with no damage but insane knock back
Instead of the slimy saddle there will be the slime skin coat it provides 5 defense and life regen
(Expert mode)
Instead of the royal jelly there will the royal crest it turns you into a slime while a slime you take no fall damage you can float while pressing the up key , you can jump very high and negate 10% of damage
As most of this is slightly op the queen slime should be as difficult as the king slime
Ideas.
The crown of the slimes
Royal jelly + the royal crest
Contains the effect of the materials mentioned above
The royal slime shield
The crown of the slimes + the shield of Cthulhu
Contains the effects of the materials mentioned above
Slime armor
5 shackles + slime skin coat
10 defense and life regen
The royal armor of slime
Slime armor + the royal slime shield
Contains the effects of the materials mentioned above
Creating the gear shouldn't be to hard and I'm sure you'll have fun creating the mini boss if you do choose to do this
Thanks